What is respiration? How does it occur?

• The process of release of energy by oxidation of food is called as respiration.
• Respiration takes place at body level and cellular level.
• In body level respiration, oxygen and carbon dioxide are exchanged between the organism and its surroundings.
• In cellular respiration, foodstuff is oxidised and energy is released.
• This energy is stored in the form of ATP.
• Organisms use this energy to carry out different functions.