Question

'Digestion of food is a chemical change but breathing is a physical process.' Explain

Answer 1

digestion is a chemical reaction as new products are formed like fatty acids, glycerol, etc. for the fat containing foods respectively, while breathing is a physical process as there is new products formed only there is exchanging of gases.
hope this helps.:)

Answer 2

digestion of food is a chemical change because chemical changes are changes that change the natural identity and produces a new substance .Hence digestion is also a chemical change because it involves the GI track and in the end produces a new substance.

breathing is not a physical process because in breathing we just take in air and take whatewer we are needing and then,it is distributed in the veins and then released.so there is no new substance forming in this and hence it is not a chemical change but a phisical change