Q5 of 12 Page 118

During exhalation, the ribs

(i) move outwards


(ii) move downwards


(iii) move upwards


(iv) do not move at all

(ii) move downwards


During exhalation, ribs move down and inwards, while diaphragm moves up to its former position. This reduces the size of the chest cavity and air is pushed out of the lungs.



More from this chapter

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5

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

(i) carbon dioxide (ii) lactic acid


(iii) alcohol (iv) water

 5

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

 6

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































Column I



Column II



(a) Yeast



(i) Earthworms



(b) Diaphragm



(ii) Gills



(c) Skin



(iii) Alcohol



(d) Leaves



(iv) Chest cavity



(e) Fish



(v) Stomata



(f) Frog



(vi) Lungs and skin


 7

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)