Solution of Chapter 10. Respiration in Organisms (NCERT Science Book)

Why does an athlete breathe faster and deeper than usual after finishing the race?

List the similarities and differences between the aerobics and anaerobic respiration.

Why do we often sneeze when we inhale a lot of dust-laden air?

Take three test-tubes. Fill 3/4th of each with water. Label them A, B and C. Keep a snail in the test- tube A, a water plant in test-tube B and in C, keep snail and plant both. Which test-tube would have the highest concentration of CO₂?

In cockroaches, air enters the body through

(i) lungs (ii) gills

(iii) spiracles (iv) skin

During heavy exercise, we get cramps in the legs due to the accumulation of

(i) carbon dioxide (ii) lactic acid

(iii) alcohol (iv) water

Normal range of breathing rate per minute in an average adult person at rest is:

(i) 9-12 (ii) 15-18

(iii) 21-24 (iv) 30-33

Correct option: (ii) 15-18

During exhalation, the ribs

(i) move outwards

(ii) move downwards

(iii) move upwards

(iv) do not move at all

Match the items in column I with those in column II.

Mark 'T' if the statement is true and 'F' if it is false:

(i) During heavy exercise the breathing rate of person slow down. (T/F)

(ii) Plants carry out photosynthesis only during the day and respiration only at night. (T/F)

(iii) Frogs breathe through their skins as well as their lungs. (T/F)

(iv) The fishes have lungs for respiration. (T/F)

(v) The size of the chest cavity increases during inhalation. (T/F)

Given below is a square of letters in which are hidden different words related to respiration in organism. These words may be present in any direction--- upwards, downwards, or along the diagonals. Find the words for your respiratory system. Clues are given below the square.

(i) The air tubes of insects.

(ii) Skeletal structures surrounding chest cavity

(iii) Muscular floor of chest cavity

(iv) Tiny pores on the surface of leaf.

(v) Small openings on the sides of the body of an insects

(vi) The respiratory organs of human beings

(vii) The openings through which we inhale

(viii) An anaerobic organism

(ix) An organism with tracheal system

The mountaineers carry oxygen with them because:

(a) At an altitude of more than 5 km there is no air.

(b) The amount of air available to a person is less than that available on the ground.

(c) The temperature of air is higher than on the ground.

(d) The pressure of air is higher than that on the ground.