Answer:
B. chemical only.
Explanation:
In the process of respiration which is a chemical process where organic compound is released. In this process exergonic reaction takes place in which compound changes into different ones.
Following are the two types of respiration:-
1] Aerobic respiration:- In this type of respiration requirement of oxygen is more and energy released is more.
2] Anaerobic respiration:- In this type of respiration oxygen requirement is less and energy released is also less.