CBSE Class 10 Answered

Breathing is the physical act that animals perform to take in oxygen rich air and expel oxygen deficient air. It is the process by which air is drawn into and out of the lungs.

Respiration is the chemical process by which cells break down energy rich molecules (glucose) to get energy to perform cellular functions. Respiration is a chemical reaction which takes place inside all living cells. Cellular respiration is a complex series of chemical reactions where sugars are broken down to release energy by the use of oxygen. The key is not the gases that are released, but the energy.

When air is in the lungs, oxygen is taken into the body. The oxygen is then used during respiration to 'burn' the food, releasing its energy. The waste CO₂ produced is passed out of the body from the lungs when we breathe out.

So, respiration and breathing are connected, but they are not the same thing.