NCERT Solutions for Class 7 science Chapter 10

Respiration in Organisms

NCERT Solutions for Class 7 Science chapter 10 Exercise Question

Question 1

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

Answer

During race athletes need a lot of energy.In order to extra energy the athlete breathes faster. Because more oxygen is supplied to our body for breakdown of food so that it released more energy .

Question 2

List the similarities and differences between aerobic and anaerobic respiration.

Answer

Similarities:
i) Both breakdown the food and released energy
ii) Both takes place inside cells

Differences

Question 3

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

Answer

When we inhale dust-laden air the dust partical trap inside nostrill and irritate the mucus lining of the nasal cavity which results in sneezing.

Question 4

Take three test-tubes. Fill 3/4th of each with water. Label them A, B and C. Keep a snail in 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 ?

Answer

Test tube A will have the highest concentration of CO₂ because snail which realease out CO₂ into the tube and in tube B and tube C there is a plant which will use CO₂ to for making of food and realease O₂ so it have less concentration of CO₂ in the tube C.

Question 5

Tick the correct answer:

(a) In cockroaches, air enters the body through

(i) lungs (ii) gills (iii) spiracles (iv) skin

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

(i) carbon dioxide (ii) lactic acid (iii) alcohol (iv) water

(c) 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

(d) During exhalation, the ribs

(i) move outwards (ii) move downwards (iii) move upwards (iv) do not move at all

Answer

a) (iii) spiracles

b) (ii) lactic acid

c) (ii) 15–18

d) (ii) move downwards

Question 6

Match the items in Column I with those in Column II:

Answer

Question 7

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

(i) During heavy exercise the breathing rate of a person slows 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)

Answer

i) False

ii) False

iii) True

iv) False

v) True

Question 8

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

(vi) The respiratory organs of human beings

(vii) The openings through which we inhale

(viii) An anaerobic organism

(ix) An organism with tracheal system

Answer

(i) Trachea

(ii) Ribs

(iii) Diaphragm

(iv) Stomata

(v) Spiracles

(vi) Lungs

(vii) Nostrils

(viii) Yeast

(ix) Ant

Question 9

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 that on the ground.

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

Answer

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