Keywords To Remember:
- Weathering: The process of breaking down rocks into smaller particles through natural forces such as wind, water, and temperature changes.
- Erosion: The gradual wearing away of rocks and soil by natural forces like wind, water, and ice.
- Deposition: The process by which sediments carried by wind, water, or ice are laid down in a new location, leading to the formation of landforms such as deltas and sand dunes.
- Geomorphology: The scientific study of the formation, structure, and change of Earth’s surface and landforms.
- Gradation: The processes of erosion, transportation, and deposition that shape the Earth’s surface over time.
- Agents of Gradation: Natural forces like running water, glaciers, wind, and sea waves that contribute to the erosion and deposition of earth materials.
- Meander: A curve or bend in a river or stream, typically formed as the water erodes the banks of the river over time.
- Glacier: A large mass of moving ice formed from the accumulation of snow over a long period. Glaciers shape landforms through erosion and deposition.
- Continental Glaciers: Large glaciers that cover vast areas of land, typically found in regions such as Antarctica and Greenland.
- Mountain Glaciers: Smaller glaciers that are typically found in mountainous regions, like the Siachin Glacier in India.
- Sand Dunes: Mounds of sand formed by the action of wind, often found in desert regions.
- Delta: A landform formed at the mouth of a river where it meets the sea, created by the deposition of sediments carried by the river.
- Humus: The dark organic material in soil formed by the decomposition of plant and animal matter, which is important for soil fertility.
- Soil Formation: The process by which rocks break down into smaller particles, which are then transported and deposited, forming soil over a long period.
- Residual Soil: Soil that forms from the weathering of the underlying rock and remains in the same location.
- Transported Soil: Soil that is carried from one place to another by natural forces like water or wind.
- Horizons: Layers of soil that develop over time, including the bedrock, weathered rock, subsoil, and topsoil.
- Soil Erosion: The process of the topsoil being worn away by wind, water, or human activities, leading to the loss of fertile land.
- Soil Conservation: Practices aimed at preventing soil erosion and maintaining soil health, such as tree planting, crop rotation, and land management.
- Alluvial Soil: Fertile soil found in river valleys, formed by the deposition of sediments carried by rivers. It is often used for agriculture.
- Black Soil: A type of soil found in the Deccan Plateau, which is fertile and known for its ability to retain moisture, commonly used for growing cotton.
- Red Soil: Soil that is rich in iron and found in regions with low rainfall, like the peninsular India.
- Laterite Soil: Soil formed in areas with heavy rainfall, often found in hill slopes. It is rich in iron and aluminum.
- Soil Fertility: The ability of soil to support plant growth, often determined by the presence of nutrients and organic material like humus.
- Sustainable Development: Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
A. Tick (✔) the correct option.
- Which one of the following is not a human activity?
(a) diverse land use
(b) cleaning of forests
(c) new human settlements
(d) formation of mountains
Answer – (d) formation of mountains
- Which one is a Continental glacier?
(a) Siachin
(b) Antarctica
(c) Gangotri
(d) Yamunotri
Answer – (b) Antarctica
- Which of the following features are formed by a river?
(a) ‘V’ shaped valley, meander and delta
(b) ‘U’ shaped valley, meander and delta
(c) ‘I’ shaped valley, cliff and delta
(d) ‘V’ shaped valley, meander and sand dunes
Answer – (a) ‘V’ shaped valley, meander and delta
- Which layer of the soil contains humus?
(a) bed rock
(b) weathered rock
(c) sub soil
(d) top soil
Answer – (d) top soil
- Which soil type is capable of retaining moisture and becomes sticky when wet?
(a) alluvial soil
(b) black soil
(c) red soil
(d) laterite soil
Answer – (b) black soil
B. Fill in the blanks.
- Organic matter when gets decomposed in the soil and converts it into dark coloured material is called ________ .
Answer – humus
- ________ soil is found in a large part of our country.
Answer – Alluvial
- ________ and ________ valleys are formed at the youthful stage of a river.
Answer – ‘V’ shaped, ‘I’ shaped
- A ________ is a steep sided rock facing the sea.
Answer – Cliff
- ________ river and ________ river form the largest delta of the world.
Answer – Ganga, Brahmaputra
C. Give a single term for each of the following statements.
- Mounds of sand deposited by wind action in deserts.
Answer – Sand dunes
- The process in which a gradual wearing and carrying away of soil particles takes place on the earth’s surface.
Answer – Erosion
- The process of laying down of sediments carried by various agents of gradation.
Answer – Deposition
- A mass of moving ice down the slope.
Answer – Glacier
- Removal of the top layer of soil.
Answer – Soil erosion
D. Answer the following questions in brief.
- Specify two differences between internal and external forces.
Answer – Internal forces are forces that originate inside the Earth, such as volcanic eruptions and earthquakes, which cause sudden and dramatic changes.
External forces work on the Earth’s surface and bring gradual changes over time, like weathering, erosion, and deposition by water, wind, and ice.
- Name the various agents of gradation.
Answer – The various agents of gradation are running water, wind, glaciers, and sea waves.
- Distinguish between transported and residual soil.
Answer – Transported soil is the soil that has been moved from its original location by external forces like wind, water, or glaciers.
Residual soil is the soil that is formed by the weathering of the parent rock and remains in the same location.
- How is a delta formed?
Answer – A delta is formed when a river carrying sediments deposits them at its mouth, where the river’s flow slows down and splits into several distributaries. Over time, this deposition creates a delta, which is typically a fan-shaped landform.
- Why is humus formed more rapidly in humid areas?
Answer – Humus forms more rapidly in humid areas because these regions support dense vegetation and have abundant plant and animal life. The warm and moist conditions accelerate the decomposition of organic matter, leading to higher humus content.
E. Answer the following questions
- Explain weathering. Mention the factors that affect the rate of weathering and soil erosion.
Answer – Weathering is the process by which rocks break down into smaller particles due to exposure to atmospheric conditions like temperature, moisture, and biological activity.
The rate of weathering and soil erosion depends on factors like:
Temperature: Extremes in temperature can cause rocks to expand and contract, breaking them apart.
Vegetation: Plants protect soil from erosion by stabilizing it with their roots.
Rainfall: Heavy rainfall can speed up weathering and erosion by washing away the soil.
Slope of the land: Steeper slopes lead to faster erosion as gravity pulls the water and soil downhill.
- Explain the formation of soil with the help of a labelled diagram.
Answer – Soil forms through the process of weathering and the breakdown of rocks. Over time, weathered material is transported by agents like wind, water, or glaciers and deposited to form soil.
Soil Formation Process:
Weathering of Parent Rock: Rocks are broken down into smaller particles.
Transportation: These particles are carried by wind, water, or glaciers.
Deposition: The particles are deposited in layers, forming soil.
Diagram (Labelled):
Topsoil: Contains organic material (humus).
Subsoil: Contains minerals and nutrients.
Weathered Rock: Layer of broken-down rock particles.
Bedrock: The solid rock underneath.
- What are the major soil types found in India? Give one important characteristic of each.
Answer – Alluvial soil: Found in the northern and coastal plains; highly fertile and used for agriculture.
Black soil: Found in the Deccan Plateau; retains moisture and is ideal for growing cotton.
Red soil: Found in the peninsular region; rich in iron content and porous.
Laterite soil: Found in the hill slopes of the peninsular plateau; formed by heavy rainfall and leaching.
- Describe the journey of a river from its source to its mouth.
Answer – A river begins its journey at its source in the mountains or hills, where it is small and flows fast due to steep slopes. As the river moves downstream, it gathers more water from tributaries and begins to slow down. In the mature stage, the river forms meanders and continues to erode the land. As it reaches the old stage, the river becomes slow and forms distributaries, depositing silt and forming a delta near its mouth, where it meets the sea.
- Why is conservation of soil important? Suggest three different ways of soil conservation.
Answer – Soil conservation is essential to prevent soil erosion, maintain soil fertility, and ensure sustainable agricultural practices. The loss of soil can lead to reduced crop yields, desertification, and environmental degradation.
Three ways of soil conservation are:
Afforestation: Planting trees to reduce soil erosion by wind and water.
Terracing: Creating steps on hilly areas to reduce runoff and soil loss.
Contour ploughing: Ploughing along the contours of the land to reduce water runoff and soil erosion.
Value Based Questions
Agriculture is the main source of livelihood in India. It depends on the fertility of the soil. When soil erodes, it makes the land less productive and lead to landslides, floods and destroys the habitat of micro-organism. Wrong agricultural practices, deforestation for the expansion of agriculture, industrialisation, construction of roads and railway lines are some of reasons of this menace.
- What will be the after effects of this menace?
Answer – The aftereffects of soil erosion and the related activities will be severe and far-reaching:
Reduced Agricultural Productivity: Soil erosion makes the land infertile, reducing crop yields and affecting the economy, especially in agricultural regions.
Increased Frequency of Landslides and Floods: Erosion weakens the soil structure, making the land more prone to landslides and floods, which can destroy infrastructure, homes, and crops.
Loss of Habitat for Micro-organisms: Soil erosion destroys the habitat of essential microorganisms that help in soil fertility, thus affecting the overall ecological balance.
Damage to Water Resources: Erosion can also lead to the siltation of rivers, affecting water quality and the availability of water for irrigation and drinking purposes.
- In your opinion, which one of the reasons mentioned above is justified?
Answer – In my opinion, deforestation for the expansion of agriculture is one of the most justified reasons. Deforestation removes the protective vegetation cover, making the soil vulnerable to erosion. The roots of plants hold the soil together, and without them, the soil is easily washed away by rain or wind. This leads to the degradation of land and the loss of fertile soil, which negatively impacts both agriculture and the environment. Sustainable land-use practices and reforestation can help mitigate this issue.
Map Skill
Take an outline map of India. Locate and label the areas of major soil types on it. Mention the names of states of each soil type.
Answer – For this task, please refer to a physical outline map of India and locate the areas of major soil types:
- Alluvial Soil: Found mainly in the Himalayan foothills, Indo-Gangetic plains, and coastal areas. States include Uttar Pradesh, Bihar, West Bengal, Punjab, Haryana, and Odisha.
- Black Soil: Found mainly in the Deccan Plateau, particularly in Maharashtra, Gujarat, Madhya Pradesh, Karnataka, and parts of Andhra Pradesh.
- Red Soil: Found in the peninsular region, particularly in Tamil Nadu, Karnataka, Andhra Pradesh, Orissa, and parts of Madhya Pradesh.
- Laterite Soil: Found in the Western Ghats, Chotanagpur Plateau, Assam, Karnataka, and Kerala.
- Desert Soil: Found in the Rajasthan and Gujarat regions.
- Mountain Soil: Found in the Himalayan regions of Jammu and Kashmir, Uttarakhand, Himachal Pradesh, and Sikkim.
Something To Do
Complete the table by writing appropriate features in relevant columns.
Answer –
Agents | Features formed by Erosion | Features formed by Deposition |
Running Water | V-shaped valleys, Meanders, Cliffs | Deltas, Floodplains, Alluvial fans |
Wind Action | Desert pavements, Blowouts | Sand dunes, Loess deposits |
Sea Waves | Cliffs, Sea caves, Stumps | Beaches, Spits, Bars |
Moving Ice | Glacial valleys, Moraines, Fjords | Glacial outwash plains, Drumlins |
- Collect pictures of various features formed by various agents of gradation and weathering. Paste these pictures in a scrap file.
Answer – For this task, you will need to collect images of features formed by agents of gradation and weathering. Examples include:
V-shaped valleys, Meanders, and Floodplains formed by running water.
Sand dunes and Desert pavements formed by wind action.
Beaches and Spits formed by sea waves.
Moraines and Glacial valleys formed by moving ice.
You can find these images in textbooks, online resources, or nature magazines. Paste them in a scrap file and label them accordingly for reference.
Additional Questions and Answers –
Fill in the Blanks
- Soil is formed by the process of _______________ and _______________.
Answer – weathering, erosion
- The primary source of energy for soil formation is _______________.
Answer – sunlight
- The process in which a river erodes its bank is known as _______________.
Answer – lateral erosion
- _______________ soil is rich in iron and is found in areas with high rainfall.
Answer – Laterite
- The mineral particles in soil are mainly made of _______________, _______________, and _______________.
Answer – sand, silt, clay
- _______________ is the type of soil found in the northern plains of India.
Answer – Alluvial soil
- _______________ soil is known for its moisture-retaining properties.
Answer – Black soil
- _______________ is the agent of gradation that forms cliffs, beaches, and sand dunes.
Answer – Wind action
- A _______________ is formed when a river deposits sediments at its mouth.
Answer – Delta
- The _______________ is the surface layer of soil that contains the most humus.
Answer: topsoil
Multiple Choice Questions (MCQs)
- Which of the following agents is responsible for forming sand dunes?
(a) Water
(b) Wind
(c) Ice
(d) Sea Waves
Answer – (b) Wind
- What type of soil is rich in clay content?
(a) Red soil
(b) Black soil
(c) Alluvial soil
(d) Desert soil
Answer – (b) Black soil
- Which of the following features is formed by a river?
(a) Cliff
(b) Sand dunes
(c) Delta
(d) Moraines
Answer – (c) Delta
- Which one of the following is a cause of soil erosion?
(a) Overgrazing
(b) Wind erosion
(c) Deforestation
(d) All of the above
Answer – (d) All of the above
- Which soil is best suited for cotton cultivation?
(a) Red soil
(b) Black soil
(c) Laterite soil
(d) Alluvial soil
Answer – (b) Black soil
- In which state of India is laterite soil found?
(a) Rajasthan
(b) Kerala
(c) Punjab
(d) Haryana
Answer – (b) Kerala
- _______________ is an example of a soil type formed due to wind action.
(a) Black soil
(b) Loess
(c) Alluvial soil
(d) Mountain soil
Answer – (b) Loess
- Which of the following is NOT a layer of soil?
(a) Humus
(b) Bedrock
(c) Crust
(d) Subsoil
Answer – (c) Crust
True/False
- True/False: Soil erosion occurs only in areas with heavy rainfall.
Answer – False
(Soil erosion can occur in both dry and wet areas depending on factors like wind, water, and human activities.)
- True/False: Alluvial soil is most commonly found in coastal regions.
Answer – False
(Alluvial soil is typically found in river valleys and flood plains, not just coastal regions.)
- True/False: The humus content in soil improves soil fertility.
Answer – True
- True/False: Soil erosion leads to the enrichment of soil.
Answer – False
(Soil erosion leads to the loss of soil nutrients, making it less fertile.)
- True/False: Black soil is rich in iron and is found in the Deccan Plateau.
Answer – True
Competency-Based Questions (CBQs)
- Q: A river has cut through the landscape, leaving behind a deep, narrow valley. What type of valley has been formed, and how does the river continue to shape this valley over time?
Answer – The river has created a V-shaped valley, which is formed during the youthful stage of the river. As the river continues to flow, it erodes the sides and deepens the valley, making it narrower at the top and steeper.
- Q: A farmer notices that his soil has lost its fertility and no longer supports healthy crops. Suggest three possible reasons for this loss of fertility and how the farmer can address the issue.
Answer – Three possible reasons for soil fertility loss include soil erosion, overuse of chemical fertilizers, and deforestation. The farmer can address these issues by implementing soil conservation techniques like terracing and crop rotation, reducing the use of chemicals, and planting more trees to prevent erosion.
- Q: A community living near a river experiences frequent flooding. What steps can be taken to prevent further erosion and damage?
Answer – The community can build levees or dams to control the flow of the river and prevent floods. Vegetation cover can be increased on the banks to prevent erosion, and the construction of silt traps can reduce the deposition of sediments in the riverbed.
High Order Thinking Skill (HOTS) Questions
- Q: Explain how the soil erosion process can affect both agricultural practices and the environment. Suggest practical solutions to reduce soil erosion.
Answer – Soil erosion can lead to the loss of fertile topsoil, which reduces the land’s ability to support crops. This affects agricultural production and can lead to food shortages. Additionally, eroded soil often ends up in water bodies, leading to pollution and poor water quality. Practical solutions include planting cover crops, building terraces, and implementing contour plowing to reduce soil displacement.
- Q: Imagine that you are a soil scientist, and you are asked to identify the soil type of a region. What key features would you look for, and how would they help you determine the type of soil?
Answer – As a soil scientist, I would look for features such as texture (sand, silt, clay), color (dark for humus-rich soils, red for iron-rich soils), moisture retention ability, and mineral content. These features would help identify soil types like black soil (for cotton cultivation) or alluvial soil (found in river valleys).
Short Questions
- Q: What is weathering?
Answer – Weathering is the process of breaking down rocks into smaller particles due to various natural factors like temperature changes, water, and biological activity.
- Q: Name the different types of soil found in India.
Answer – The different types of soil found in India are alluvial soil, black soil, red soil, laterite soil, desert soil, and mountain soil.
- Q: What is the importance of humus in soil?
Answer – Humus is important for soil because it improves its fertility, helps retain moisture, and supports the growth of microorganisms that enhance soil health.
- Q: What causes soil erosion?
Answer – Soil erosion is caused by factors like wind, water, deforestation, and overgrazing, which remove the topsoil from the land.
Long Questions (60-70 words)
- Q: Explain the formation of a delta.
Answer – A delta is formed when a river carrying sediments reaches a body of water, such as a sea or lake, and slows down. The sediment is deposited in the water, forming a triangular or fan-shaped landform. Over time, this process builds up layers of sediment, creating a delta. The Ganga-Brahmaputra delta in India is an example.
- Q: What are the causes and effects of soil erosion, and what can be done to prevent it?
Answer – Soil erosion is caused by factors like wind, water, deforestation, and overgrazing. Its effects include loss of fertile soil, reduced agricultural productivity, and increased flooding. To prevent it, practices like terracing, planting vegetation, and contour ploughing can be adopted to hold the soil together and reduce erosion.
Additional Questions and Answers – 02
Questions and Answers on Earth’s Surface Changes
Fill in the Blanks Questions and Answers
- Question: The surface of the earth constantly undergoes ______ changes.
Answer: The surface of the earth constantly undergoes sudden - Question: Sudden changes originate inside the earth due to ______ or earthquake activities.
Answer: Sudden changes originate inside the earth due to volcanic or earthquake activities. - Question: Gradual changes occur due to natural forces like carrying of soil by ______.
Answer: Gradual changes occur due to natural forces like carrying of soil by rain water. - Question: Human factors like ______ of forests contribute to changes in the earth’s surface.
Answer: Human factors like cutting down of forests contribute to changes in the earth’s surface. - Question: Any process working on the earth’s surface is known as ______ process.
Answer: Any process working on the earth’s surface is known as external - Question: The term ______ refers to the process that breaks rocks into smaller particles.
Answer: The term weathering refers to the process that breaks rocks into smaller particles. - Question: ______ refers to the gradual wearing and carrying away of loose particles.
Answer: Erosion refers to the gradual wearing and carrying away of loose particles. - Question: Deposition refers to the laying down of ______ carried by agents of gradation.
Answer: Deposition refers to the laying down of sediments carried by agents of gradation. - Question: A river in its early stage is called ______ and has a high rate of erosion.
Answer: A river in its early stage is called young and has a high rate of erosion. - Question: In the plains, a river flows through ______ during its maturity stage.
Answer: In the plains, a river flows through meanders during its maturity stage. - Question: The river deposits silt, sand, and sediments near its mouth, forming a ______.
Answer: The river deposits silt, sand, and sediments near its mouth, forming a delta. - Question: The largest delta in the world is formed by the ______ and Brahmaputra rivers.
Answer: The largest delta in the world is formed by the Ganga and Brahmaputra rivers. - Question: A mass of moving ice is called a ______.
Answer: A mass of moving ice is called a glacier. - Question: In India, glaciers are found in the high altitudes of the ______.
Answer: In India, glaciers are found in the high altitudes of the Himalayas. - Question: Wind is an agent of gradation most common in ______ regions.
Answer: Wind is an agent of gradation most common in desert - Question: Strong winds can form strange shaped rocks like ______ rocks.
Answer: Strong winds can form strange shaped rocks like mushroom - Question: Sea waves erode rocks along the coast, forming steep-sided ______.
Answer: Sea waves erode rocks along the coast, forming steep-sided cliffs. - Question: Soil is made of ______ and inorganic particles.
Answer: Soil is made of organic and inorganic particles. - Question: The organic particles in soil form a dark-colored material called ______.
Answer: The organic particles in soil form a dark-colored material called humus. - Question: ______ soil is very fertile and found in northern and coastal plains of India.
Answer: Alluvial soil is very fertile and found in northern and coastal plains of India.
Multiple Choice Questions and Answers
- Question: What causes sudden changes on the earth’s surface?
a) Wind
b) Volcanic activities
c) Rain water
d) Construction of roads
Answer: b) Volcanic activities - Question: Which of the following is a gradual change on the earth’s surface?
a) Earthquake
b) Changes in the course of a river
c) Volcanic eruption
d) Mining
Answer: b) Changes in the course of a river - Question: Which human activity contributes to changing the earth’s surface?
a) Planting trees
b) Large-scale mining
c) Protecting wildlife
d) Crop rotation
Answer: b) Large-scale mining - Question: What is an external process?
a) A process inside the earth
b) A process working on the earth’s surface
c) A process in the atmosphere
d) A process in the ocean
Answer: b) A process working on the earth’s surface - Question: What does weathering do to rocks?
a) Deposits them
b) Breaks them into smaller particles
c) Carries them away
d) Forms new rocks
Answer: b) Breaks them into smaller particles - Question: What is erosion also known as?
a) Deposition
b) Weathering
c) Denudation
d) Sedimentation
Answer: c) Denudation - Question: What does deposition involve?
a) Breaking of rocks
b) Laying down of sediments
c) Carrying away of particles
d) Formation of glaciers
Answer: b) Laying down of sediments - Question: What is a key factor affecting the rate of erosion?
a) Color of soil
b) Slope of the land
c) Type of rocks
d) Size of glaciers
Answer: b) Slope of the land - Question: In which stage does a river have the highest rate of erosion?
a) Old stage
b) Maturity stage
c) Young stage
d) Delta stage
Answer: c) Young stage - Question: What feature does a river form in its young stage?
a) Meanders
b) Delta
c) V-shaped valleys
d) Sand dunes
Answer: c) V-shaped valleys - Question: What happens to a river in its old stage?
a) It flows over steep mountains
b) It forms meanders
c) It deposits silt and forms a delta
d) It erodes rapidly
Answer: c) It deposits silt and forms a delta - Question: Where is the largest delta in the world located?
a) Nile River
b) Ganga and Brahmaputra Rivers
c) Amazon River
d) Mississippi River
Answer: b) Ganga and Brahmaputra Rivers - Question: What is a glacier?
a) A mass of moving water
b) A mass of moving ice
c) A type of soil
d) A type of rock
Answer: b) A mass of moving ice - Question: Where are glaciers found in India?
a) Deccan Plateau
b) Northern Plains
c) Himalayas
d) Coastal Plains
Answer: c) Himalayas - Question: Where is the action of wind most common as an agent of gradation?
a) Forests
b) Deserts
c) Mountains
d) Rivers
Answer: b) Deserts - Question: What does strong wind form in desert regions?
a) V-shaped valleys
b) Sand dunes
c) Meanders
d) Cliffs
Answer: b) Sand dunes - Question: What do sea waves form along the coast due to erosion?
a) Sand dunes
b) Cliffs
c) Deltas
d) Meanders
Answer: b) Cliffs - Question: What are the organic particles in soil derived from?
a) Rocks
b) Dead remains of plants and animals
c) Sand dunes
d) Glaciers
Answer: b) Dead remains of plants and animals - Question: What type of soil is known as cotton soil?
a) Alluvial soil
b) Black soil
c) Red soil
d) Laterite soil
Answer: b) Black soil - Question: What is the removal of the top layer of soil called?
a) Weathering
b) Deposition
c) Soil erosion
d) Gradation
Answer: c) Soil erosion
True/False Questions and Answers)
- Question: Sudden changes on the earth’s surface are caused by volcanic activities.
Answer: True - Question: Gradual changes are caused only by human activities.
Answer: False (Gradual changes are caused by natural forces like rain water, winds, etc.) - Question: Construction of roads is a natural process that changes the earth’s surface.
Answer: False (It is a human activity.) - Question: External processes work inside the earth.
Answer: False (External processes work on the earth’s surface.) - Question: Weathering breaks rocks into smaller particles.
Answer: True - Question: Erosion refers to the deposition of sediments.
Answer: False (Erosion refers to the wearing and carrying away of particles.) - Question: Deposition results in the formation of soil at new places.
Answer: True - Question: The rate of erosion depends on the color of the soil.
Answer: False (It depends on factors like temperature, vegetation, rainfall, etc.) - Question: A young river flows over steep mountains with a high rate of erosion.
Answer: True - Question: In its maturity stage, a river forms a delta.
Answer: False (It forms a delta in its old stage.) - Question: The Ganga and Brahmaputra delta is the largest in the world.
Answer: True - Question: Glaciers are found in the Deccan Plateau in India.
Answer: False (They are found in the Himalayas.) - Question: Wind is an agent of gradation most active in forest regions.
Answer: False (It is most active in desert regions.) - Question: Strong winds can form mushroom rocks in deserts.
Answer: True - Question: Sea waves deposit material to form cliffs along the coast.
Answer: False (Sea waves erode rocks to form cliffs.) - Question: Organic particles in soil form humus, which contributes to fertility.
Answer: True - Question: Humus is abundant in desert soil.
Answer: False (Humus is low in desert soil.) - Question: Alluvial soil is found in the Deccan Plateau.
Answer: False (It is found in northern and coastal plains.) - Question: Soil erosion is caused only by natural processes.
Answer: False (It is also caused by human practices like deforestation and overgrazing.) - Question: Soil conservation can be achieved through crop rotation and multiple cropping.
Answer: True
Competency-Based Questions and Answers
- Question: A farmer notices that soil on his hilly land is washing away during heavy rains. Which process is occurring, and what can he do to prevent it?
Answer: The process is soil erosion, caused by running water. He can prevent it by planting trees, practicing crop rotation, and creating terraces to reduce the slope and slow down water flow. - Question: During a field trip, you observe a river forming a V-shaped valley in a mountainous area. What stage is the river in, and what process is dominant?
Answer: The river is in its young stage, as it flows over steep mountains. The dominant process is erosion, forming features like V-shaped valleys due to down-cutting. - Question: A coastal village notices cliffs forming along the shore due to continuous wave action. Which agent of gradation is at work, and what feature is being formed?
Answer: Sea waves are the agent of gradation at work, eroding the rocks. This continuous erosion forms steep-sided cliffs along the coast. - Question: A desert area in Rajasthan has sand dunes forming due to strong winds. What process is occurring, and what agent is responsible?
Answer: The process of deposition is occurring as wind slows down and deposits sand. The agent responsible is wind, which is a common agent of gradation in desert regions. - Question: A student learns that a glacier in the Himalayas is melting and depositing sediments in a valley. What process is this, and what type of glacier is likely involved?
Answer: The process is deposition, as the melting glacier deposits sediments. The glacier is likely a mountain glacier, such as the Siachin or Gangotri glacier, found in the Himalayas. - Question: A farmer in the Deccan Plateau grows cotton successfully on black soil. Why is this soil suitable, and what is its common name?
Answer: Black soil retains moisture and becomes sticky when wet, making it ideal for cotton. It is commonly known as cotton soil due to its suitability for cotton cultivation. - Question: A region experiences heavy rainfall, leading to the formation of laterite soil on hill slopes. What process causes this, and where is it found?
Answer: Laterite soil forms due to the leaching process in heavy rainfall areas. It is found on the hill slopes of the peninsular plateau in India. - Question: You observe that a river in the plains is winding and forming meanders. What stage is the river in, and why does this happen?
Answer: The river is in its maturity stage. Meanders form because the slope of the land decreases, slowing the river’s speed and causing it to wind through the plains. - Question: A student sees that deforestation in an area has led to soil erosion. What human activity caused this, and what can be done to mitigate it?
Answer: Deforestation, the cutting down of forests, caused soil erosion by removing vegetation cover. Mitigation includes reforestation, adopting selective agricultural practices like crop rotation, and raising awareness about soil conservation. - Question: A delta is forming at the mouth of a river you visit. What stage is the river in, and what materials are being deposited to form the delta?
Answer: The river is in its old stage, as it deposits materials near its mouth. It deposits silt, sand, and sediments, forming a delta, like the Ganga-Brahmaputra delta.
High Order Thinking Skills (HOTS) Questions and Answers
- Question: Why do you think sudden changes like volcanic eruptions have a more immediate impact on the earth’s surface compared to gradual changes like river course changes?
Answer: Sudden changes like volcanic eruptions cause immediate, visible destruction, altering landscapes rapidly through lava flows or ash deposits. Gradual changes, like river course changes, occur over centuries, slowly reshaping the land through erosion and deposition, allowing ecosystems to adapt over time without immediate disruption. - Question: How might climate change affect the agents of gradation like running water and glaciers, and what could be the consequences for the earth’s surface?
Answer: Climate change can increase rainfall, enhancing river erosion, or melt glaciers faster, increasing deposition in valleys. This could lead to more flooding, altered river courses, and loss of glacial features, reshaping the earth’s surface and affecting ecosystems, agriculture, and human settlements in those areas. - Question: Why is the formation of a delta significant for both the environment and human activities, and how does it relate to the river’s life cycle?
Answer: A delta, formed in a river’s old stage, enriches the environment with fertile soil, supporting agriculture and biodiversity. For humans, deltas like the Ganga-Brahmaputra provide arable land for farming. The river’s life cycle ends here, depositing silt and sediments, creating new landforms that sustain ecosystems and human livelihoods. - Question: How do human activities like industrialization and deforestation disrupt the natural balance of external processes, and what are the long-term effects?
Answer: Industrialization and deforestation accelerate erosion by removing vegetation and increasing runoff, disrupting natural weathering and deposition. Long-term effects include soil degradation, loss of fertile land, increased flooding, and reduced biodiversity, as ecosystems struggle to adapt to rapid changes, affecting agriculture and environmental stability. - Question: Why might the rate of erosion be higher in areas with less vegetation cover, and how does this impact soil formation?
Answer: Less vegetation cover exposes soil to agents like water and wind, increasing erosion rates as there are no roots to hold soil in place. This hinders soil formation by removing the topsoil rich in humus, slowing the deposition process and reducing fertility, leading to degraded land over time. - Question: How does the formation of different soil types, like alluvial and laterite, reflect the influence of external processes in various regions?
Answer: Alluvial soil forms through deposition by rivers in plains, reflecting the role of running water in transporting sediments. Laterite soil forms in heavy rainfall regions through leaching, showing weathering’s impact. These processes highlight how external agents like water and climate shape soil types based on regional conditions. - Question: Why is soil erosion considered a serious global problem, and how can sustainable practices mitigate its effects?
Answer: Soil erosion removes the fertile topsoil, reducing crop yields and degrading land, impacting food security globally. Sustainable practices like afforestation, crop rotation, and multiple cropping prevent erosion by stabilizing soil, enhancing vegetation cover, and improving land management, ensuring long-term fertility and ecological balance. - Question: How do the characteristics of black soil make it suitable for cotton farming, and what does this indicate about the relationship between soil and agriculture?
Answer: Black soil retains moisture and becomes sticky when wet, providing ideal conditions for cotton, which needs consistent water. This shows how soil properties directly influence agricultural practices, as specific crops thrive in soils with suitable texture and moisture retention, shaping regional farming patterns. - Question: Why might wind be a more dominant agent of gradation in desert regions compared to regions with dense vegetation?
Answer: Desert regions have little rainfall and sparse vegetation, leaving soil exposed to strong winds that erode and deposit loose particles, forming sand dunes. Dense vegetation in other regions anchors soil, reducing wind’s impact, making it less dominant compared to water or other agents of gradation. - Question: How do the layers of soil (horizons) reflect the long-term process of soil formation, and why is the topmost layer critical for agriculture?
Answer: Soil horizons, from bedrock to topsoil, show weathering and deposition over thousands of years, with each layer reflecting a stage of soil development. The topmost layer, rich in humus, is critical for agriculture as it provides nutrients and fertility, supporting plant growth and ensuring high crop yields.
Short Questions and Answers
- Question: What causes sudden changes on the earth’s surface?
Answer: Volcanic or earthquake activities. - Question: Name one natural force causing gradual changes.
Answer: Carrying of soil by rain water. - Question: What human activity changes the earth’s surface?
Answer: Cutting down of forests. - Question: What is an external process?
Answer: A process working on the earth’s surface to bring changes. - Question: What does weathering do to rocks?
Answer: Breaks them into smaller particles. - Question: What is erosion also known as?
Answer: Denudation. - Question: What does deposition involve?
Answer: Laying down of sediments at new places. - Question: Name one factor affecting the rate of erosion.
Answer: Slope of the land. - Question: In which stage does a river erode the most?
Answer: Young stage. - Question: What feature does a young river form?
Answer: V-shaped valleys. - Question: What does a river form in its old stage?
Answer: A delta. - Question: What is the largest delta in the world?
Answer: Ganga and Brahmaputra delta. - Question: What is a glacier?
Answer: A mass of moving ice. - Question: Where are mountain glaciers found in India?
Answer: In the Himalayas. - Question: Where is wind most active as an agent of gradation?
Answer: In desert regions. - Question: What does strong wind form in deserts?
Answer: Sand dunes. - Question: What do sea waves form along the coast?
Answer: Cliffs. - Question: What forms humus in soil?
Answer: Organic particles from dead plants and animals. - Question: Which soil is known as cotton soil?
Answer: Black soil. - Question: What is the removal of topsoil called?
Answer: Soil erosion.
Long Questions and Answers (60-70 Words)
- Question: Explain how a river acts as an agent of gradation throughout its life cycle.
Answer: A river, as an agent of gradation, erodes steep mountains in its young stage, forming V-shaped valleys. In its maturity stage, it flows through meanders in the plains with reduced speed. In its old stage, it deposits silt, sand, and sediments near its mouth, forming a delta, like the Ganga-Brahmaputra delta, the largest in the world, shaping the earth’s surface through erosion and deposition. - Question: Describe the process of weathering and its effects on the earth’s surface.
Answer: Weathering breaks rocks into smaller particles through exposure to weather changes, including erosion and deposition. It affects the earth’s surface by disintegrating rocks, flaking stone monuments, and rusting iron railings. This process lowers land levels by wearing away particles and contributes to soil formation when combined with deposition, gradually altering landscapes and enabling new landforms over time. - Question: How do glaciers contribute to changes in the earth’s surface, and where are they found in India?
Answer: Glaciers, as masses of moving ice, erode loose particles and rocks, transporting and depositing them upon melting, forming new landforms like valleys. In India, glaciers are found in the high altitudes of the Himalayas, such as the Siachin and Gangotri glaciers. These mountain glaciers shape the landscape by eroding and depositing materials, significantly altering the earth’s surface over time. - Question: Discuss the role of wind as an agent of gradation in desert regions.
Answer: In desert regions with little rainfall and sparse vegetation, wind acts as a powerful agent of gradation. It erodes loose rock particles, rubs and scrapes rocks to form strange shapes like mushroom rocks, and deposits materials as sand dunes when its speed slows down. In India, such sand dunes are found in western Rajasthan, showcasing wind’s impact on the landscape. - Question: What is soil erosion, and how can it be prevented through sustainable practices?
Answer: Soil erosion is the removal of the top layer of soil, reducing fertility and crop yields, often due to deforestation and overgrazing. It can be prevented through sustainable practices like planting trees to stabilize soil, adopting crop rotation and multiple cropping to maintain soil health, and developing pastureland management, ensuring long-term fertility and reducing land degradation globally. - Question: Explain the formation of soil and the different horizons involved in the process.
Answer: Soil formation is a slow process taking thousands of years, starting with weathering breaking rocks into particles, which are carried and deposited by water or wind. Soil develops in layers called horizons: bedrock at the bottom, followed by weathered rock, subsoil, and topsoil. The topmost horizon, rich in humus, supports plant growth, reflecting the gradual accumulation of organic and inorganic materials. - Question: Describe the characteristics of alluvial soil and its significance in India.
Answer: Alluvial soil, formed by river deposition, is found in India’s northern and coastal plains. It is very fertile, making it ideal for agriculture, supporting crops over large areas. Its fertility comes from the rich sediments deposited by rivers, forming the major agricultural land of the country, contributing significantly to India’s food production and economic stability through farming. - Question: How do human activities like deforestation and industrialization impact the earth’s surface?
Answer: Deforestation and industrialization remove vegetation and increase runoff, accelerating soil erosion and altering landforms. They disrupt natural processes like weathering and deposition, leading to loss of fertile soil, increased flooding, and habitat destruction. These activities, including construction of roads and mining, change the earth’s surface, necessitating sustainable development to maintain ecological balance and preserve resources for future generations. - Question: What are the characteristics of black soil, and why is it suitable for cotton farming?
Answer: Black soil, found in the Deccan Plateau, retains moisture and becomes sticky when wet, making it ideal for cotton farming, which requires consistent water. It is confined to parts of Gujarat, Maharashtra, and Karnataka. Known as cotton soil, its ability to hold water supports cotton growth, reflecting how soil properties influence agricultural practices in specific regions. - Question: Discuss the role of sea waves as an agent of gradation along coastal areas.
Answer: Sea waves, as a powerful agent of gradation along coasts, continuously strike and erode rocks, forming steep-sided cliffs. The eroded materials are then deposited along the shore, creating beaches. This dual process of erosion and deposition by sea waves shapes coastal landscapes, altering the earth’s surface and creating distinct features like cliffs and beaches over time