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

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

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.