NCERT PRACTICE QUESTIONS
1. Match structures given in Column I with functions given in Column II.
Ans.-
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) The blood from the heart is transported to all parts of the body by the .
(ii) Haemoglobin is present in cells.
(iii) Arteries and veins are joined by a network of .
(iv) The rhythmic expansion and contraction of the heart is called .
(v) The main excretory product in human beings is .
(vi) Sweat contains water and .
(vii) Kidneys eliminate the waste materials in the liquid form called .
(viii) Water reaches great heights in the trees because of suction pull caused by .
Ans.-
(i) The blood from the heart is transported to all parts of the body by the arteries .
(ii) Haemoglobin is present in red blood cells.
(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 (ii) phloem (iii) stomata (iv) root hair
(b) Water absorption through roots can be increased by keeping the plants
(i) in the shade (ii) in dim light (iii) under the fan (iv) covered with a polythene bag
Ans.- a) i) Xylem iii) under the fan
4. Why is transport of materials necessary in a plant or in an animal? Explain.
Ans.- (a) To transport food to various parts of the body. (b) Animals need to transport wastes to parts from where they can be removed.
5. What will happen if there are no platelets in the blood?
Ans.- If there are no platelets, then blood will not clot as platelets release blood clotting factor at the site of injury.
6. What are stomata? Give two functions of stomata.
Ans,- Tiny pores present on the leaf surface are known as stomata. Functions of stomata - (a) Helps in exchange of gases (b) Evaporation of water through leaves occurs due to stomata.
7. Does transpiration serve any useful function in the plants? Explain.
Ans.- (a) Helps in lowering temperature of plants, thus preventing heat injury of plants. (b) Helps in transpiration pull, which helps in raining water in higher plants. (c) It also causes loss of water absorbed by plants.
8. What are the components of blood?
Ans.- Red blood cells, white blood cells, platelets and plasma.
9. Why is blood needed by all the parts of a body?
Ans.- (a) For the transport of oxygen to all parts of our body. (b) To expel out carbon dioxide from our body. (c) To transmit heat thus helping in the regulation of body temperature. (d) It is required to fight out infections and diseases.
10. What makes the blood look red?
Ans.- Haemoglobin, a red pigment present in the blood makes it look red.
11. Describe the function of the heart.
Ans.- The heart is an organ which beats continuously to act as a pump for the transport of blood, which carries other substances with it. The heart has four chambers. The two upper chambers are called the atria (singular: atrium), and the two lower chambers are called the ventricles. The partition between the chambers helps to avoid mixing up of blood-rich in oxygen with the blood-rich in carbon dioxide. Blood flows from the heart to the lungs and back to the heart from where it is pumped to the rest of the body.
12. Why is it necessary to excrete waste products?
Ans.- When our cells perform their functions, certain waste products are released. These are toxic and hence need to be removed from the body.
13. Draw a diagram of the human excretory system and label the various parts.
Ans.-
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