Which is true for both photosynthesis and cellular respiration? a. they are simple chemical reactions.
b. they are complex chemical reactions.
c. they require light energy from the sun.
d. they require cells to use water.

The equation for photosynthesis is carbon dioxide + water + light = sugar + oxygen. The equation for cellular respiration is sugar + oxygen = carbon dioxide + water + released energy. Water is involved in both reactions, but it is a byproduct in respiration. Since chemicals have changed into other chemicals, a chemical reaction is taking place - but it is hard to say whether it is simple or complex.

Organism, organ system, organs, tissue, cells