Question

Is respiration a physical or a chemical change give reasons

Answer 1

Glucose is oxidised to CO2 and H2O (along with release of energy) at the cells by the oxygen from air we breathe in. Since glucose is converted into new products with different composition, respiration is a chemical change

Answer 2

Respiration is a process in which oxidation of food takes places which releases energy.

Respiration is a chemical process because, oxygen is taken in which helps in the oxidation of food to release energy. This energy is used to do various activities. Hence, respiration is a chemical process.