Question

what is respiration? how does it occur?​

Answer 1

$\sf \pmb{Answer :}$

(i) The process of release of energy by oxidation of food is called as respiration. (ii) In living organisms, respiration occurs at two levels-body and cellular level. (iii) In case of body level, oxygen and carbon dioxide are exchanged between the body and surrounding.

Answer 2

Respiration is the process of inspiration and expiration of air in simple words. It occurs when the diaphragm relaxes and contracts. Inspiration occurs when the diaphragm contracts while expiration occurs when diaphragm relaxes.