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Science Class 7 Chapter 10 Respiration in Organisms – NCERT Exercise Solution (Question-Answer)

CBSE Science Class 7- Chapter 10- Respiration in Organisms – NCERT Exercise Solution (Question-Answer) is provided below. Total 9 Questions are in this NCERT Chapter Exercise, all are solved here.

Q1. Why does an athlete breathe faster and deeper than usual after finishing the race?

Answer: During the race, an athlete consumes lots of energy, and they need lots of oxygen to release the energy. Hench, an athlete breathes faster and deeper than usual finishing the race.

Anaerobic respiration occurs during running or other physical activity.

Q2. List the similarities and differences between aerobic and anaerobic respiration.

Answer: Difference between aerobic and anaerobic respiration:

  Aerobic Anaerobic
It occurs in the presence of oxygenIt occurs in the absence of oxygen
Glucose is completely converted to release carbon dioxide, water and energy.Glucose is incompletely converted to release alcohol, carbon dioxide, water and energy.
Energy is stored inside the body in the form of ATP.Energy is not stored as ATP.
More amount of energy released.Less amount of energy is released.
It occurs in all plants and animals, that is, all organisms.It occurs in yeast, bacteria, parasitic worms and human muscles.

Similarities between aerobic and anaerobic respiration.

(i) In both respiration, food Is broken down into finer constituents to release energy.

(ii) Both takes place inside cells and both produce byproducts.

Q3. Why do we often sneeze when we inhale a lot of dust-laden air?

Answer: We often sneeze when we inhale a lot of dust-laden air because of dust air cause irritation in our nose. The foreign particles get passed the hair present in the nose to the Nasal cavity and irritate the lining of the cavity which results in sneezing.

Q4. Take three test-tube. Fill ¾th 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: The test-tube A has the highest concentration because snail which present in test-tube A will expels out CO2 into the tube and inhale O2.

In the test-tube B there is plant which inhale CO­2 and expel O2.

In test-tube C there is snail and plant both present so in both cases, the concentration of CO2 is less.

Q5. Tick the correct answer:

(a) In cockroaches, air enters the body through

(i) lungs

(ii) gills

(iii) spiracles

(iv) skin

Answer: (iii) spiracles

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

 (i) carbon dioxide

(ii) lactic acid

(iii) alcohol

Answer: (ii) lactic acid

(c) The 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

Answer: (ii) 15-18

(d) During exhalation, the ribs

(i) move outwards

(ii) move downwards

(iii) move upwards

(iv) do not move at all

Answer: (ii) move downwards

Q6.Match the items in column I with those in column II:

  Column I   Column II
(a) Yeast(i) Earthworm
(b) Diaphragm(ii) Gills
(c) Skin(iii) Alcohol
(d) Leaves(iv) Chest cavity
(e) Fish(v) Stomata
(f) Frog(vi) Lungs and skin
 (vii) Tracheae


  Column IColumn II
(a) Yeast(iii) Alcohol
(b) Diaphragm(iv) Chest cavity
(c) Skin(i) Earthworm
(d) Leaves(v) Stomata
(e) Fish(ii) Gills
(f) Frog(vi) Lungs and skin

Q7. 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)

Answer: False

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

Answer: False

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

Answer: True

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

Answer: False

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

Answer: True

Q8. 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 about those words are given below the square.




(i) The air tubes of insects

Answer: Trachea

(ii) Skeletal structures surrounding chest cavity

Answer: Ribs

(iii) Muscular floor of chest cavity

Answer: Diaphragm

(iv) Tiny pores on the surface of leaf

Answer: Stomata

(v) Small opening on the sides of the body of an insect

Answer: Spiracles

(vi) The respiratory organs of human beings

Answer: Lungs

(vii) The opening through which we inhale

Answer: Nostrils

(viii) An anaerobic organism

Answer: Yeast

(ix) An organism with tracheal system

Answer: Ant

Q9 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

(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

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