Keywords To Remember
Keyword | Definition |
Diffusion | The movement of particles from a region of higher concentration to a region of lower concentration. |
Osmosis | The movement of water molecules through a semi-permeable membrane from a region of low solute concentration to a high solute concentration. |
Xylem | The plant tissue that transports water and minerals from roots to other parts of the plant. |
Phloem | The plant tissue that transports food (mainly sugars) from leaves to other parts of the plant. |
Stomata | Tiny openings on the surface of leaves that control gas exchange and water loss through transpiration. |
Translocation | The process of transporting food (mainly sucrose) through the phloem from leaves to other parts of the plant. |
Capillaries | The smallest blood vessels where exchange of gases, nutrients, and waste occurs between blood and body tissues. |
Red Blood Cells (RBCs) | Blood cells that carry oxygen using haemoglobin; they give blood its red color. |
White Blood Cells (WBCs) | Blood cells that fight infections by attacking bacteria, viruses, and foreign substances. |
Platelets | Small cell fragments in blood that help in clotting to prevent blood loss during injury. |
Blood Plasma | The yellowish liquid part of blood that carries cells and dissolved substances like nutrients, hormones, and waste products. |
Valve | A structure in veins and the heart that prevents the backflow of blood, ensuring it flows in only one direction. |
Arteries | Thick-walled blood vessels that carry oxygen-rich blood away from the heart to the rest of the body. |
Veins | Thin-walled blood vessels that return oxygen-poor blood from the body to the heart. |
Heart Beat | The rhythmic contraction and relaxation of heart muscles that pump blood through the body. |
Pulse | The rhythmic throbbing of arteries caused by the beating of the heart, often felt at the wrist or neck. |
Urine | A liquid waste product formed by the kidneys, composed of water, urea, and other waste materials. |
Sweat | A liquid produced by sweat glands in the skin, containing water, salts, and small amounts of urea, helping to cool the body and excrete waste. |
Carbon Dioxide (CO₂) | A gas produced as a waste during respiration; removed from the body via the lungs. |
Haemoglobin | An iron-containing protein in RBCs that binds to oxygen and transports it throughout the body. |
Septum | The muscular wall that divides the left and right sides of the heart. |
Atrium (Atria) | The upper chambers of the heart that receive blood entering the heart. |
Ventricle | The lower chambers of the heart that pump blood out of the heart. |
Systole | The phase of the heartbeat when the heart muscles contract and pump blood. |
Diastole | The phase of the heartbeat when the heart muscles relax and fill with blood. |
Excretion | The biological process by which waste products of metabolism are removed from the body. |
Kidneys | Bean-shaped organs that filter blood to remove urea and other waste, forming urine. |
Ureters | Tubes that carry urine from the kidneys to the urinary bladder. |
Urinary Bladder | The organ that stores urine before it is excreted from the body. |
Urethra | The duct through which urine is discharged from the bladder to the outside of the body. |
Egestion | The removal of undigested food material from the body through the anus. |
Homeostasis | The process by which living organisms maintain a stable internal environment despite external changes. |
Circulatory System | The body system responsible for the movement of blood, nutrients, gases, and wastes throughout the body. |
Respiratory System | The system responsible for taking in oxygen and expelling carbon dioxide through breathing. |
Metabolic Waste | Waste substances produced by the chemical processes in cells during metabolism, such as urea and carbon dioxide. |
Tissue Fluid | The fluid that surrounds the cells in tissues, formed when blood plasma leaks out of capillaries, facilitating exchange of materials with cells. |
Something To Know
A. Fill in the blanks.
- Water and minerals are transported, to various parts of a plant, by a network of tubes, called the ___________ .
Answer – xylem
- ___________ is the respiratory carrier in blood.
Answer – Haemoglobin
- The upper chambers of heart are known as ___________ while the lower chambers are known as ___________.
Answer – atria, ventricles
- ___________ is the muscular wall that divides the heart length-wise.
Answer – Septum
- Excretion, in unicellular plants and animals, takes place through ___________.
Answer – diffusion
B. Write True or False for the following statements.
- Phloem transports food, from the leaves, to the other parts of the plant.
Answer – True
- Transpiration is harmful for the plants.
Answer – False
- Oxygenated blood, from the lungs, flows into the left atrium and then to all other parts of the body.
Answer – True
- Arteries carry the oxygen-deficient blood, back to the heart.
Answer – False
- Platelets help in the clotting of blood.
Answer – True
- The red colour of the blood is due to the presence of plasma.
Answer – False
- Urine is passed out of the body through the urethra.
Answer – True
C. Tick (✓) the correct option.
- A process, that helps in transportation, in unicellular organisms is—
locomotion
diffusion
absorption
respiration
Answer – diffusion
- In plants, water is transported by the-
stomata
root hair
phloem
xylem
Answer – xylem
- The blood vessels, having thick, elastic walls, are called—
arteries
capillaries
veins
atria
Answer – arteries
- Which part of the blood has haemoglobin?
WBCs
RBCs
blood platelets
plasma
Answer – RBCs
- Urine gets collected in the—
ureter
urethra
kidney
urinary bladder
Answer – urinary bladder
D. Answer the following questions in brief.
- What will happen if the xylem tissue gets damaged in a branch of a tree?
Answer – Water and minerals will not reach that branch, causing it to dry and eventually die.
- Define transpiration.
Answer – Transpiration is the evaporation of water from the plant surface, mainly from the stomata of leaves.
- Name the three types of blood vessels.
Answer – Arteries, veins, and capillaries.
- State any two functions of the blood.
Answer – Blood transports oxygen and nutrients to body parts, and helps fight infections through WBCs.
- Define the term ‘pulse rate’.
Answer – Pulse rate is the number of heartbeats per minute, felt as rhythmic throbbing in the arteries.
E. Answer the following questions
- Briefly explain the transport of water and minerals in plants.
Answer – Roots absorb water and minerals from the soil. These are transported through the xylem vessels to various parts of the plant. Transpiration helps in pulling water upwards, especially in tall plants.
- Describe, in brief, the function of heart.
Answer – The heart pumps oxygenated blood to the body and deoxygenated blood to the lungs. It works continuously by contracting (systole) and relaxing (diastole).
- State the functions of the three types of blood vessels.
Answer – Arteries carry oxygen-rich blood from the heart.
Veins carry deoxygenated blood to the heart.
Capillaries connect arteries and veins and exchange substances with tissues.
- Give one function each of RBC, WBC and platelets.
Answer – RBC: Carry oxygen.
WBC: Fight infections.
Platelets: Help in clotting blood.
- Draw a neat and well labelled diagram of the human excretory system.
Answer – Please draw the diagram yourself. It should include: kidneys, ureters, urinary bladder, urethra. Students will do this at their own.
Value Based Question
Mr. Vidhwan, a very dedicated, disciplined and devoted teacher, decided to spend his post retirement life in his village. He spent his time there in helping the village children to acquire the basic skills of the three R’s. The village elders would often say: “Mr. Vidhwan spends all his time in transporting his knowledge and skills to our children. He is as important to us as the roots arc to the plants.”
- State the values displayed by Mr. Vidhwan.
Answer – Dedication, selflessness, love for education, and community service.
- Name the substance and its source which is transported to other parts of the plant by (a) roots (b) leaves.
Answer – (a) Roots — Water and minerals from soil.
(b) Leaves — Food (glucose) prepared during photosynthesis.
- Try to read the ‘life story’ of any person who ‘transported’ her/his knowledge/skill/ wealth to the ‘society at large’. Share your story with the other students in the class.
Answer – (Example) Dr. A.P.J. Abdul Kalam, known as the ‘Missile Man of India’, dedicated his knowledge in aerospace and science for India’s development and inspired millions of students through his teachings and books.
Something To Do
- Find out about two human diseases related to the circulatory system. Try to find out their causes and their cure.
Answer – Hypertension: Caused by stress, poor diet, lack of exercise. Controlled through medication, diet, and lifestyle changes.
Atherosclerosis: Caused by cholesterol build-up in arteries. Treated with medication, lifestyle changes, or surgery.
- Make an improvised Stethoscope using a plastic funnel, a rubber tube, a balloon and a rubber band. Measure, and compare, the heart beat of all the members of your family using this.
Answer – (Encourage to follow instructions given in the text and use it to measure family members’ heartbeats.)
- Have you ever thought of the excretory products of plants and their importance to us? Try to find out the basic details related to these products and give their uses.
Answer – Yes, plants excrete resins, gums, latex, and essential oils.
Gums are used in food and medicine.
Latex is used to make rubber.
Resins are used in varnishes and perfumes.
Additional Questions and Answers – 01
Fill in the Blanks (with Answers)
- The process by which plants lose water in the form of vapor is called __________.
Answer: Transpiration - Blood is pumped from the heart to all body parts through __________.
Answer: Arteries - The main organs of the human excretory system are the __________.
Answer: Kidneys - The __________ filter the blood to form urine.
Answer: Nephrons - __________ are the blood cells responsible for fighting infections.
Answer: White Blood Cells (WBCs) - Food is transported in plants through a tissue called __________.
Answer: Phloem - Veins carry blood __________ the heart.
Answer: Towards - The loss of excess water through stomata helps in __________ the plant.
Answer: Cooling - The rhythmic contraction and relaxation of heart muscles is known as __________.
Answer: Heartbeat - The fluid part of blood is called __________.
Answer: Plasma
Multiple Choice Questions (MCQs with Answers)
- Which part of the plant absorbs water and minerals?
Leaves
B. Roots
C. Stem
D. Flowers
Answer: B. Roots - The basic filtration unit in the kidneys is called—
Neuron
B. Nephron
C. Nephritis
D. Glomerulus
Answer: B. Nephron - Which blood component carries carbon dioxide?
Plasma
B. RBC
C. WBC
D. Platelets
Answer: A. Plasma - Which blood vessel carries blood from the heart to the lungs?
Pulmonary vein
B. Pulmonary artery
C. Aorta
D. Vena cava
Answer: B. Pulmonary artery - Which of these is an excretory product in humans?
Sweat
B. Oxygen
C. Glucose
D. Bile
Answer: A. Sweat - Transpiration mainly occurs through—
Roots
B. Bark
C. Stomata
D. Xylem
Answer: C. Stomata - The blood vessel that brings oxygenated blood from lungs to heart is—
Pulmonary vein
B. Aorta
C. Pulmonary artery
D. Vena cava
Answer: A. Pulmonary vein - The function of the phloem is to—
Absorb sunlight
B. Transport water
C. Transport food
D. Produce glucose
Answer: C. Transport food
True or False (with Answers)
- Platelets help in digestion.
False - Blood is a connective tissue.
True - Plants do not have an excretory system.
True - Arteries usually carry oxygen-rich blood.
True - Kidneys help in removing nitrogenous wastes from the body.
True - The heart is made up of skeletal muscles.
False - Plasma is red in color.
False - The transport system in plants includes xylem and phloem.
True
Short Answer Questions (with Answers)
- What is the function of red blood cells?
Answer: Red blood cells transport oxygen from the lungs to all parts of the body. - What is transpiration?
Answer: The process of loss of water from plant leaves through stomata is called transpiration. - What are veins?
Answer: Veins are blood vessels that carry blood toward the heart, usually deoxygenated. - Why is blood red in color?
Answer: Blood is red due to the presence of haemoglobin in red blood cells. - What is excretion?
Answer: The process of removing waste products from the body is called excretion.
Competency-Based (Reasoning and Assertion) Questions
- Assertion: Xylem helps in the transport of water and minerals.
Reason: Xylem is made up of living cells that conduct food.
Both Assertion and Reason are true and Reason is the correct explanation.
B. Both Assertion and Reason are true but Reason is not the correct explanation.
C. Assertion is true but Reason is false.
D. Both Assertion and Reason are false.
Answer: C. Assertion is true but Reason is false. - Assertion: Transpiration helps in cooling the plant.
Reason: Water evaporates from the leaf surface, taking away heat.
Answer: A. Both Assertion and Reason are true and Reason is the correct explanation. - Assertion: Arteries have thick muscular walls.
Reason: Arteries carry blood under high pressure from the heart.
Answer: A. Both Assertion and Reason are true and Reason is the correct explanation.
High Order Thinking Skills (HOTS) Questions
- Why does the heart have two separate chambers for oxygenated and deoxygenated blood?
Answer: This prevents the mixing of oxygen-rich and oxygen-poor blood, ensuring efficient oxygen supply to the body. - What would happen if phloem in a plant stops working?
Answer: The plant would be unable to transport food from leaves to other parts, leading to starvation of tissues and possible plant death. - How does the structure of arteries suit their function?
Answer: Arteries have thick, elastic walls to withstand and maintain the high pressure of blood pumped by the heart.
Long Answer Questions (50–60 words)
- Explain the process of transportation of water in plants.
Answer: Water and minerals are absorbed by root hairs and transported upward through the xylem vessels. The movement is assisted by capillary action, root pressure, and transpiration pull. As water evaporates from leaves during transpiration, it creates a suction force that pulls water upward from the roots. - Describe the role of the circulatory system in humans.
Answer: The circulatory system, comprising the heart, blood, and blood vessels, transports oxygen, nutrients, hormones, and waste products throughout the body. The heart pumps blood, arteries carry it away from the heart, and veins return it. It also regulates body temperature and protects against infections through white blood cells. - What is excretion and why is it important in humans?
Answer: Excretion is the removal of metabolic waste products like urea and excess salts. Kidneys filter blood and produce urine, which is stored in the bladder and passed out through the urethra. Excretion is essential to maintain internal chemical balance and prevent the accumulation of toxic substances in the body.
Additional Questions and Answers – 02
Fill in the Blanks Questions and Answers
- Question: The process of movement of substances in an organism is called ______.
Answer: The process of movement of substances in an organism is called transportation. - Question: In unicellular organisms, transportation occurs through ______ and osmosis.
Answer: In unicellular organisms, transportation occurs through diffusion and osmosis. - Question: Transpiration in plants is the evaporation of water from the ______ on leaves.
Answer: Transpiration in plants is the evaporation of water from the stomata on leaves. - Question: Transpiration creates a ______ pull that helps water reach tall trees.
Answer: Transpiration creates a suction pull that helps water reach tall trees. - Question: The circulatory system in animals includes the heart, blood vessels, and ______.
Answer: The circulatory system in animals includes the heart, blood vessels, and blood. - Question: The heart is divided into left and right sides by a muscular wall called ______.
Answer: The heart is divided into left and right sides by a muscular wall called septum. - Question: ______ carry oxygen-rich blood from the heart to the body.
Answer: Arteries carry oxygen-rich blood from the heart to the body. - Question: ______ carry oxygen-deficient blood back to the heart.
Answer: Veins carry oxygen-deficient blood back to the heart. - Question: Blood contains RBCs, WBCs, platelets, and a liquid component called ______.
Answer: Blood contains RBCs, WBCs, platelets, and a liquid component called blood plasma. - Question: ______ in RBCs transports oxygen in the body.
Answer: Haemoglobin in RBCs transports oxygen in the body. - Question: WBCs protect the body by fighting ______.
Answer: WBCs protect the body by fighting infections. - Question: Blood platelets help in the ______ of blood to prevent excessive bleeding.
Answer: Blood platelets help in the clotting of blood to prevent excessive bleeding. - Question: A heartbeat consists of a contraction called systole and a relaxation called ______.
Answer: A heartbeat consists of a contraction called systole and a relaxation called diastole. - Question: The normal human heart beats ______ to 80 times per minute at rest.
Answer: The normal human heart beats 60 to 80 times per minute at rest. - Question: The removal of wastes from living organisms is called ______.
Answer: The removal of wastes from living organisms is called excretion. - Question: In higher animals, the ______ process wastes like urea to produce urine.
Answer: In higher animals, the kidneys process wastes like urea to produce urine. - Question: The lungs remove ______ dioxide during exhalation.
Answer: The lungs remove carbon dioxide during exhalation. - Question: The skin removes small amounts of waste through ______.
Answer: The skin removes small amounts of waste through sweat. - Question: Plants transport water and minerals through the ______ tissue.
Answer: Plants transport water and minerals through the xylem - Question: Food in plants is transported by the ______ tissue.
Answer: Food in plants is transported by the phloem
Multiple Choice Questions and Answers
- Question: What is transportation in living organisms?
a) Removal of wastes
b) Movement of substances within the body
c) Production of energy
d) Absorption of food
Answer: b) Movement of substances within the body - Question: How do unicellular organisms transport substances?
a) Through blood vessels
b) Through diffusion and osmosis
c) Through the heart
d) Through stomata
Answer: b) Through diffusion and osmosis - Question: What is transpiration in plants?
a) Absorption of water
b) Evaporation of water from plant surfaces
c) Transport of food
d) Production of oxygen
Answer: b) Evaporation of water from plant surfaces - Question: What is one benefit of transpiration in plants?
a) It increases body temperature
b) It creates a suction pull for water transport
c) It removes oxygen
d) It produces food
Answer: b) It creates a suction pull for water transport - Question: What does the circulatory system in animals consist of?
a) Heart, lungs, and kidneys
b) Heart, blood vessels, and blood
c) Skin, blood, and veins
d) Arteries, veins, and kidneys
Answer: b) Heart, blood vessels, and blood - Question: What divides the heart into left and right sides?
a) Valve
b) Atrium
c) Septum
d) Ventricle
Answer: c) Septum - Question: Which blood vessels carry oxygen-rich blood from the heart?
a) Veins
b) Capillaries
c) Arteries
d) Plasma
Answer: c) Arteries - Question: What prevents backflow of blood in veins?
a) Thick walls
b) Valves
c) High pressure
d) Capillaries
Answer: b) Valves - Question: What component of blood transports oxygen?
a) WBCs
b) Platelets
c) Haemoglobin in RBCs
d) Blood plasma
Answer: c) Haemoglobin in RBCs - Question: What is the role of WBCs in the body?
a) Transport oxygen
b) Fight infections
c) Clot blood
d) Carry carbon dioxide
Answer: b) Fight infections - Question: What do blood platelets help with?
a) Transporting oxygen
b) Clotting of blood
c) Fighting infections
d) Carrying nutrients
Answer: b) Clotting of blood - Question: What is blood plasma?
a) The cell component of blood
b) The liquid component of blood
c) The oxygen carrier in blood
d) The waste removal system
Answer: b) The liquid component of blood - Question: What is systole in a heartbeat?
a) Relaxation of heart muscles
b) Contraction of heart muscles
c) Blood flow in veins
d) Blood flow in arteries
Answer: b) Contraction of heart muscles - Question: What is the normal human heart rate at rest?
a) 20 to 40 beats per minute
b) 60 to 80 beats per minute
c) 100 to 120 beats per minute
d) 150 to 200 beats per minute
Answer: b) 60 to 80 beats per minute - Question: What is excretion in living organisms?
a) Movement of substances
b) Removal of wastes
c) Transport of oxygen
d) Production of energy
Answer: b) Removal of wastes - Question: Which organ removes urea from the body as urine?
a) Lungs
b) Skin
c) Kidneys
d) Heart
Answer: c) Kidneys - Question: What waste do the lungs remove during exhalation?
a) Urea
b) Carbon dioxide
c) Sweat
d) Faeces
Answer: b) Carbon dioxide - Question: How does the skin contribute to excretion?
a) By removing carbon dioxide
b) By producing urine
c) By eliminating sweat
d) By transporting oxygen
Answer: c) By eliminating sweat - Question: Which plant tissue transports water and minerals?
a) Phloem
b) Xylem
c) Stomata
d) Capillaries
Answer: b) Xylem - Question: Which plant tissue transports food?
a) Xylem
b) Phloem
c) Arteries
d) Veins
Answer: b) Phloem
True/False Questions and Answers
- Question: Transportation is the movement of substances within an organism.
Answer: True - Question: Diffusion and osmosis are sufficient for transportation in multicellular organisms.
Answer: False (They are not sufficient due to time constraints.) - Question: Transpiration is the evaporation of water from plant stomata.
Answer: True - Question: Transpiration increases the plant’s body temperature.
Answer: False (It lowers the temperature.) - Question: The circulatory system in animals includes the heart, blood vessels, and blood.
Answer: True - Question: The heart is divided into left and right sides by a valve.
Answer: False (It’s divided by the septum.) - Question: Arteries carry oxygen-deficient blood to the body.
Answer: False (They carry oxygen-rich blood.) - Question: Veins have valves to prevent backflow of blood.
Answer: True - Question: Haemoglobin in RBCs transports oxygen in the body.
Answer: True - Question: WBCs are responsible for clotting blood.
Answer: False (Platelets are responsible.) - Question: Blood platelets help prevent excessive bleeding.
Answer: True - Question: Blood plasma is the cell component of blood.
Answer: False (It’s the liquid component.) - Question: A heartbeat consists of systole and diastole.
Answer: True - Question: The normal human heart rate at rest is 60 to 80 beats per minute.
Answer: True - Question: Excretion is the removal of wastes from living organisms.
Answer: True - Question: Kidneys remove carbon dioxide from the body.
Answer: False (They remove urea as urine.) - Question: The lungs remove carbon dioxide during exhalation.
Answer: True - Question: The skin removes waste through sweat.
Answer: True - Question: Xylem transports food in plants.
Answer: False (It transports water and minerals.) - Question: Phloem transports food in plants.
Answer: True
Short Questions and Answers
- Question: What is transportation in living organisms?
Answer: Movement of substances within the body. - Question: How do unicellular organisms transport substances?
Answer: Through diffusion and osmosis. - Question: What is transpiration in plants?
Answer: Evaporation of water from plant stomata. - Question: What is one benefit of transpiration?
Answer: Creates a suction pull for water transport. - Question: What does the circulatory system in animals consist of?
Answer: Heart, blood vessels, and blood. - Question: What divides the heart into left and right sides?
Answer: Septum. - Question: What do arteries carry?
Answer: Oxygen-rich blood to the body. - Question: What prevents backflow in veins?
Answer: Valves. - Question: What transports oxygen in blood?
Answer: Haemoglobin in RBCs. - Question: What is the role of WBCs?
Answer: Fight infections. - Question: What do blood platelets do?
Answer: Help in blood clotting. - Question: What is blood plasma?
Answer: The liquid component of blood. - Question: What is systole in a heartbeat?
Answer: Contraction of heart muscles. - Question: What is the normal human heart rate at rest?
Answer: 60 to 80 beats per minute. - Question: What is excretion?
Answer: Removal of wastes from living organisms. - Question: Which organ removes urea as urine?
Answer: Kidneys. - Question: What waste do the lungs remove?
Answer: Carbon dioxide. - Question: How does the skin excrete waste?
Answer: Through sweat. - Question: Which plant tissue transports water?
Answer: Xylem. - Question: Which plant tissue transports food?
Answer: Phloem.
Competency-Based Questions and Answers (Reasoning and Assertion)
- Question: Assertion (A): Transpiration is beneficial to plants.
Reason (R): It creates a suction pull that helps transport water to tall trees.
Answer: Both A and R are true, and R is the correct explanation of A. Transpiration, as stated, evaporates water from stomata, creating a suction pull that draws water up to great heights in tall trees, aiding transport and also helping regulate plant temperature, making it beneficial. - Question: Assertion (A): Arteries have thick walls compared to veins.
Reason (R): Blood flows through arteries at a high pressure.
Answer: Both A and R are true, and R is the correct explanation of A. Arteries carry blood from the heart at high pressure, as noted, requiring thick, elastic walls to withstand it, while veins, with lower pressure, have thinner walls, explaining the structural difference in blood vessels. - Question: Assertion (A): Veins have valves.
Reason (R): Valves prevent the backflow of blood towards the heart.
Answer: A is true, but R is false. Veins have valves, as stated, but they prevent backflow away from the heart, ensuring blood flows towards it, not as R suggests. This ensures efficient return of deoxygenated blood to the heart despite lower pressure in veins. - Question: Assertion (A): Blood helps fight infections.
Reason (R): WBCs in the blood destroy harmful bacteria.
Answer: Both A and R are true, and R is the correct explanation of A. Blood contains WBCs, as mentioned, which destroy harmful bacteria and defend against infections, explaining how blood plays a key role in the body’s immune response, protecting it from diseases. - Question: Assertion (A): The heart pumps oxygenated blood to the body.
Reason (R): Oxygenated blood from the lungs flows into the left atrium.
Answer: Both A and R are true, and R is the correct explanation of A. Oxygenated blood from the lungs enters the left atrium, as described, and the heart pumps it through the left ventricle to the body via arteries, ensuring oxygen delivery for cellular functions. - Question: Assertion (A): Kidneys are important for excretion in animals.
Reason (R): They process wastes like urea to produce urine.
Answer: Both A and R are true, and R is the correct explanation of A. Kidneys filter blood to remove wastes like urea, producing urine, as stated, which is then expelled, making them essential for excretion and maintaining the body’s internal balance by removing toxic metabolic wastes. - Question: Assertion (A): The skin helps in excretion.
Reason (R): It removes small amounts of waste through sweat.
Answer: Both A and R are true, and R is the correct explanation of A. The skin, through sweat glands, excretes small amounts of waste like urea via sweat, as noted, while also cooling the body, demonstrating its role in both excretion and temperature regulation in animals. - Question: Assertion (A): Xylem transports water in plants.
Reason (R): Water is absorbed by roots and moved to other plant parts.
Answer: Both A and R are true, and R is the correct explanation of A. Xylem, as mentioned, transports water and minerals absorbed by roots to leaves and other parts, supporting photosynthesis and growth, explaining its role in the plant’s water transport system effectively. - Question: Assertion (A): Pulse rate increases during exercise.
Reason (R): The heart beats faster to supply more oxygen to muscles.
Answer: Both A and R are true, and R is the correct explanation of A. During exercise, the body needs more oxygen, so the heart beats faster, as noted, increasing the pulse rate up to 200 beats per minute, ensuring muscles receive sufficient oxygen for energy production. - Question: Assertion (A): Blood plasma makes up 55% of blood volume.
Reason (R): It holds the blood cells in suspension.
Answer: Both A and R are true, and R is the correct explanation of A. Blood plasma, a straw-colored liquid, constitutes 55% of blood volume, as stated, and suspends RBCs, WBCs, and platelets, enabling their transport throughout the body, facilitating the blood’s role in circulation and nutrient delivery.
High Order Thinking Skills (HOTS) Questions and Answers
- Question: Why might transpiration be considered a necessary evil in plants, and what does this suggest about the balance between water loss and plant survival?
Answer: Transpiration is a necessary evil as it loses water but creates a suction pull to transport water to tall trees and cools the plant, as noted. This suggests plants balance water loss with survival—transpiration supports nutrient transport and temperature regulation, but excessive loss could dehydrate them, highlighting the need for water management. - Question: How does the structure of arteries and veins reflect their functions, and what does this indicate about the circulatory system’s efficiency?
Answer: Arteries have thick, elastic walls to handle high-pressure blood flow from the heart, while veins have thinner walls and valves to prevent backflow at lower pressure, as described. This indicates the circulatory system’s efficiency—specialized vessels ensure unidirectional, high-pressure delivery and low-pressure return, optimizing oxygen and waste transport throughout the body. - Question: Why might the flexibility of RBC membranes be crucial for their function, and what does this reveal about the role of structural adaptations in circulation?
Answer: RBC membranes’ flexibility allows them to bend and pass through tiny capillaries, delivering oxygen to tissues, as stated. This reveals structural adaptations are vital in circulation—RBCs’ shape ensures efficient oxygen transport to even the smallest vessels, highlighting how cellular design enhances the circulatory system’s ability to support body functions. - Question: How does the heart’s structure support its role in circulation, and what does this suggest about the importance of compartmentalization in biological systems?
Answer: The heart’s septum and valves separate oxygenated and deoxygenated blood, ensuring efficient pumping to the body and lungs, as described. This suggests compartmentalization in biological systems is crucial—dividing the heart into chambers prevents mixing, optimizing oxygen delivery and waste removal, showing how specialized structures enhance systemic efficiency in organisms. - Question: Why might the kidneys process blood so frequently, and what does this indicate about the body’s need to maintain homeostasis?
Answer: Kidneys process 1100-2000 liters of blood daily, purifying it every four minutes, as noted, to remove toxic wastes like urea. This indicates the body’s need for homeostasis—frequent filtration maintains blood composition, prevents toxin buildup, and ensures metabolic balance, highlighting the kidneys’ critical role in sustaining a stable internal environment. - Question: How does the skin’s role in excretion and temperature regulation demonstrate its multifunctionality, and what does this suggest about organ systems in animals?
Answer: The skin excretes waste via sweat and cools the body through sweat evaporation, as stated, showing its multifunctionality. This suggests animal organ systems are integrated—organs like the skin perform multiple roles, such as excretion and thermoregulation, ensuring survival by addressing diverse physiological needs through coordinated functions in a single system. - Question: Why might a maize plant lose 245 liters of water in a season, and what does this reveal about the scale of transpiration in plant physiology?
Answer: A maize plant loses 245 liters of water through transpiration to transport nutrients and cool itself, as mentioned, due to large leaf surface areas. This reveals the scale of transpiration in plant physiology—significant water loss is necessary for survival, emphasizing the importance of water absorption and management in plants’ daily functions. - Question: How does William Harvey’s discovery of blood circulation impact modern medicine, and what does this indicate about the role of experimentation in science?
Answer: William Harvey’s discovery of blood circulation, through experiments, established how blood flows and valves function, as noted, enabling modern treatments like heart surgery. This indicates experimentation is fundamental in science—empirical evidence drives understanding of biological systems, leading to advancements in medical practices that save lives and improve health outcomes. - Question: Why might pulse rate increase during exercise, and what does this suggest about the body’s response to physical stress?
Answer: Pulse rate increases during exercise, up to 200 beats per minute, to supply more oxygen to muscles, as stated, meeting higher energy demands. This suggests the body responds to physical stress by enhancing circulation—faster heartbeats ensure adequate oxygen delivery, showing how the circulatory system adapts dynamically to maintain performance under stress. - Question: How does the xylem and phloem’s roles in plants demonstrate division of labour, and what does this reveal about efficiency in multicellular organisms?
Answer: Xylem transports water and minerals, while phloem transports food, as described, showing division of labour in plants. This reveals efficiency in multicellular organisms—specialized tissues handle specific tasks, ensuring optimal resource distribution, supporting growth, and highlighting how specialization enhances survival by streamlining essential processes in complex organisms.
Long Questions and Answers (50-60 Words)
- Question: Describe the process of transpiration in plants.
Answer: Transpiration is the evaporation of water from plant stomata on leaves, as stated, where excess water absorbed from the soil is released as vapor. It creates a suction pull, transporting water to tall trees, and cools the plant in summers, acting as a necessary evil to balance water use and support nutrient transport effectively. - Question: Explain the structure and function of the heart in animals.
Answer: The heart, a hollow muscle, is divided by a septum into left and right sides, each with an atrium and ventricle, as described. It pumps oxygenated blood from the lungs via the left atrium to the body and deoxygenated blood from the right atrium to the lungs, ensuring efficient circulation for oxygen delivery and waste removal. - Question: Discuss the differences between arteries and veins.
Answer: Arteries carry oxygen-rich blood from the heart at high pressure, having thick, elastic walls, as noted, while veins carry oxygen-deficient blood back to the heart at lower pressure, with thinner walls and valves to prevent backflow. These differences ensure efficient blood flow, supporting the circulatory system’s role in oxygen and waste transport throughout the body. - Question: Describe the components of blood and their functions.
Answer: Blood comprises RBCs with haemoglobin to transport oxygen, WBCs to fight infections, platelets for clotting to prevent bleeding, and blood plasma, a liquid holding cells, as stated. Together, they distribute nutrients, maintain body temperature, fight infections, and transport oxygen and carbon dioxide, ensuring the body’s survival and efficient functioning through circulation. - Question: Explain the role of kidneys in excretion in animals.
Answer: Kidneys in animals filter blood, processing 1100-2000 liters daily, to remove wastes like urea, producing urine, as mentioned. Urine passes through ureters to the bladder and is expelled via the urethra, ensuring toxic waste removal, maintaining blood composition, and supporting homeostasis, highlighting the kidneys’ critical role in the excretory system. - Question: Discuss how the skin contributes to excretion and temperature regulation.
Answer: The skin excretes small amounts of waste like urea through sweat and regulates temperature by producing sweat, which evaporates to cool the body, as noted. With blood capillaries and sweat glands, the skin manages heat loss and waste elimination, demonstrating its dual role in maintaining body temperature and supporting excretion in animals. - Question: Describe the roles of xylem and phloem in plant transportation.
Answer: Xylem transports water and minerals from roots to other plant parts, supporting photosynthesis, while phloem transports food from leaves to other areas, as described. These conducting tissues ensure efficient nutrient and water distribution, enabling growth and survival, demonstrating the specialized roles of plant tissues in transportation for multicellular plants. - Question: Explain how blood helps maintain body temperature and fight infections.
Answer: Blood distributes heat through circulation, maintaining body temperature, and contains WBCs that fight infections by destroying harmful bacteria, as stated. By transporting oxygen and nutrients, blood supports metabolic activities, while its immune function protects against diseases, ensuring overall health and stability in the body’s internal environment through its multifaceted roles. - Question: Discuss the significance of William Harvey’s discovery of blood circulation.
Answer: William Harvey’s discovery showed blood circulates in a loop, with valves in veins ensuring flow towards the heart, as noted, revolutionizing medicine. It established experimentation’s importance, enabling modern treatments like heart surgery, and proved the circulatory system’s role in oxygen delivery, significantly advancing understanding of biological functions and medical practices. - Question: Describe how pulse rate is measured and its changes during exercise.
Answer: Pulse rate is measured by counting the straw’s movements on the wrist, reflecting heartbeats, as described in the activity, typically 60-80 beats per minute at rest. During exercise, it increases up to 200 beats per minute to supply more oxygen to muscles, ensuring energy demands are met, showing the body’s adaptive response to physical activity.