Answers to Exercises
1. Match structures given in Column I with functions given in Column II.
| Column I | Column II |
|---|---|
| (i) Stomata | (b) Transpiration |
| (ii) Xylem | (d) Transport of water |
| (iii) Root hairs | (a) Absorption of water |
| (iv) Phloem | (c) Transport of food |
2. Fill in the blanks.
(i) Haemoglobin is present in red blood cells (RBCs).
(ii) The blood from the heart is transported to all parts of the body by arteries.
(iii) Arteries and veins are joined by a network of capillaries.
(iv) The rhythmic expansion and contraction of the heart is called heartbeat.
(v) The main excretory product in human beings is urea.
(vi) Sweat contains water and salts.
(vii) Kidneys eliminate the waste materials in the liquid form called urine.
(viii) Water reaches great heights in the trees because of suction pull caused by transpiration.
3. Choose the correct option:
(a) In plants, water is transported through:
(i) xylem
(b) Water absorption through roots can be increased by keeping the plants:
(iii) under the fan
4. Why is transport of materials necessary in a plant or in an animal? Explain.
Answer: Transport of materials is essential because:
- In plants, water and minerals are transported to leaves for photosynthesis, and food is transported to all parts for energy.
- In animals, oxygen, nutrients, and hormones need to reach all body parts, and waste products need to be removed.
5. What will happen if there are no platelets in the blood?
Answer: If there are no platelets in the blood, blood will not clot, leading to excessive bleeding even from small injuries.
6. What are stomata? Give two functions of stomata.
Answer:
Stomata are tiny pores on the surface of leaves.
Functions:
- Facilitate exchange of gases (oxygen and carbon dioxide).
- Allow transpiration, helping in water movement and cooling the plant.
7. Does transpiration serve any useful function in the plants? Explain.
Answer: Yes, transpiration is useful because:
- It creates a suction pull to transport water and minerals to great heights.
- It cools the plant and maintains its temperature.
8. What are the components of blood?
Answer: The components of blood are:
- Plasma – The liquid part that carries nutrients, hormones, and waste.
- Red blood cells (RBCs) – Transport oxygen.
- White blood cells (WBCs) – Fight infections.
- Platelets – Help in blood clotting.
9. Why is blood needed by all the parts of a body?
Answer: Blood is needed to:
- Supply oxygen and nutrients.
- Remove carbon dioxide and waste products.
- Transport hormones to regulate bodily functions.
10. What makes the blood look red?
Answer: The red color of blood is due to the presence of haemoglobin, a red pigment in red blood cells.
11. Describe the function of the heart.
Answer: The heart acts as a pump to:
- Circulate oxygen-rich blood from the lungs to the body.
- Transport carbon dioxide-rich blood from the body to the lungs for removal.
12. Why is it necessary to excrete waste products?
Answer: Excretion is necessary to remove toxic substances like urea and ammonia, which can harm the body if accumulated.
13. Draw a diagram of the human excretory system and label the various parts.
Answer:
A labeled diagram includes:
- Kidneys
- Ureters
- Urinary bladder
- Urethra
(Ensure you include all the parts in your drawing.)
Extended Learning – Activities and Projects
- Blood Groups and Their Importance:
Blood groups (A, B, AB, O) are critical in blood transfusions. Mismatched transfusions can cause severe reactions. The universal donor is O, and the universal recipient is AB. - ECG (Electrocardiogram):
ECG is a medical test to measure the electrical activity of the heart. It helps in diagnosing heart conditions like irregular heartbeat or heart attack. You can learn about the different waves and their significance through a doctor’s explanation or research.
Questions and Answers on Transportation in Animals and Plants
1. What is the function of blood in our body?
Answer: Blood transports oxygen, nutrients, and hormones to different parts of the body. It also carries waste products to be removed.
2. Why is blood red?
Answer: Blood is red because of the presence of hemoglobin in red blood cells, which binds with oxygen.
3. What are the main components of blood?
Answer: The main components of blood are plasma, red blood cells (RBCs), white blood cells (WBCs), and platelets.
4. What is the role of hemoglobin?
Answer: Hemoglobin helps in transporting oxygen from the lungs to different parts of the body.
5. What are platelets?
Answer: Platelets are blood cells that help in clotting blood to prevent excessive bleeding when injured.
6. What are arteries?
Answer: Arteries are blood vessels that carry oxygen-rich blood from the heart to all parts of the body.
7. What are veins?
Answer: Veins are blood vessels that carry carbon dioxide-rich blood from the body back to the heart.
8. What are capillaries?
Answer: Capillaries are thin, tiny blood vessels that connect arteries and veins and allow the exchange of substances between blood and tissues.
9. What is a pulse?
Answer: Pulse is the throbbing movement felt in arteries due to the blood flow. It represents heartbeats.
10. What is the normal pulse rate in a resting adult?
Answer: The normal pulse rate in a resting adult is between 72–80 beats per minute.
11. What is the function of the heart?
Answer: The heart acts as a pump to circulate blood throughout the body.
12. How many chambers does the heart have?
Answer: The heart has four chambers: two atria (upper chambers) and two ventricles (lower chambers).
13. Why does the heart have a partition between its chambers?
Answer: The partition prevents the mixing of oxygen-rich and carbon dioxide-rich blood.
14. What is a stethoscope?
Answer: A stethoscope is a device used by doctors to listen to heartbeats and check the condition of the heart.
15. What is excretion?
Answer: Excretion is the process of removing waste products produced in the cells of living organisms.
16. What is the excretory system in humans?
Answer: The excretory system consists of kidneys, ureters, urinary bladder, and urethra.
17. What is the function of kidneys?
Answer: Kidneys filter waste products from the blood and form urine.
18. What is dialysis?
Answer: Dialysis is a process where an artificial kidney filters the blood of a person whose kidneys have failed.
19. How do aquatic animals excrete waste?
Answer: Aquatic animals excrete ammonia directly into the surrounding water.
20. How do plants transport water and minerals?
Answer: Plants transport water and minerals through a vascular tissue called xylem.
21. What is the role of phloem in plants?
Answer: Phloem transports food prepared in the leaves to all parts of the plant.
22. What are root hairs?
Answer: Root hairs are tiny extensions of roots that increase the surface area for absorbing water and minerals.
23. What is transpiration?
Answer: Transpiration is the process by which water evaporates from the stomata of leaves, creating a suction pull that helps transport water.
24. How does transpiration help plants?
Answer: Transpiration cools the plant and helps in the upward movement of water.
25. Why do some plants appear fresh after being placed in water?
Answer: Plants absorb water through their xylem, which makes them fresh and firm.
26. What happens to water absorbed by plants that is not used?
Answer: Unused water is released into the atmosphere through transpiration.
27. Why do birds and reptiles excrete uric acid?
Answer: Birds and reptiles excrete uric acid because it is a water-conserving mechanism, suitable for their dry environments.
28. Why does a person sweat on a hot day?
Answer: Sweating cools the body by evaporating water from the skin.
29. Why is blood donation important?
Answer: Blood donation saves lives by providing blood for people who need it due to surgeries, injuries, or illnesses.
30. What is the importance of the circulatory system?
Answer: The circulatory system transports nutrients, oxygen, and waste products throughout the body, maintaining homeostasis and supporting life.
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