An important difference between cellular respiration and photosynthesis is that when cellular respiration begins, glucose molecules are split. however, when photosynthesis begins adp molecules are split. water molecules are split. oxygen molecules are split. carbon dioxide molecules are split.

The right answer is water molecules are split.

Photolysis is part of photosynthesis, which occurs in granules (thylakoid clusters) of chloroplasts. During photolysis, light absorbed by chlorophyll is converted into chemical energy that is used to split water into hydrogen and oxygen. Oxygen is released as a by-product while hydrogen binds to the NADP coenzyme to form NADPH.

"a.) well–developed vascular system."