Question

Where does all this energy come from for our daily life activities such as absorption, transport, movement, reproduction or even breathing?

Answer 1

Part 1: Aerobic respiration
The breakdown of organic substances in the presence of oxygen, to produce energy molecules is called aerobic respiration. The substrates used for respiration include various nutrients like proteins, fats and carbohydrates. Thus the energy for all the metabolic activities within the human body comes from aerobic respiration.