Class 7 Science - Chapter Respiration in Organisms NCERT Solutions | Take three test-tubes. Fill æth of
Take three test-tubes. Fill æth 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?
Three test-tubes are taken and labelled A, B and C. Each test- tube is half filled with water.
(a) In test-tube A, a snail is kept,
(b) In test-tube B, a water plant is kept, and
(c) In test-tube C contains both a snail and a water plant.
(a) Test-tube A contains a snail in water. The snail will use up oxygen for respiration and produce carbon dioxide.
(b) Test-tube B contains a ‘water plant’ in water. The water plant will do photosynthesis by using carbon dioxide and water and produce oxygen. The water plant will use some of this oxygen for respiration and produce carbon dioxide will then be used by the plant in photosynthesis.
(c) Test-tube C contains both, a snail and a water plant. The carbon dioxide produced by the snail through the respiration is used by the plant for the synthesis of food and oxygen is released by the plant which is used by the snail for the respiration.
From the above, we conclude that the test-tube A containing only snail will have the highest concentration of carbon dioxide because there is no plant to use up the carbon dioxide produced during the respiration in snail.
More Questions From Class 7 Science - Chapter Respiration in Organisms
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Why does an athlete breathe faster and deeper than usual after finishing the race?
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List the similarities and differences between aerobic and anaerobic respiration.
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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 - Q:-
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) 9ñ12 (ii) 15ñ18
(iii) 21ñ24 (iv) 30ñ33(d) During exhalation, the ribs
(i) move outwards (ii) move downwards
(iii) move upwards (iv) do not move at all - Q:-
Mark ëTí if the statement is true and ëFí 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) - Q:-
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. - Q:-
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 ó 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
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Column I Column II
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