Photosynthesis and cellular respiration are cells occur in cells.
a)chemical reactions.
b)physical reactions

A) chemical reactions.

Explanation:

"Photosynthesis is the process through which plants convert light energy into chemical energy. Here is the chemical reaction involved: As we can see, water and carbon dioxide combine to form glucose and oxygen. Since new chemical species are formed, photosynthesis is clearly a chemical change. "

it should be briana that has it to me

a. to encourage apoptosis