Question

1. the oxygen released during photosynthesis comes directly from the splitting of

water
carbon dioxide
glucose
atp

Explanation:

In photosynthesis, the light - dependent reactions involve the splitting of water molecules ($\ce{H_2O}$). This process, called photolysis, breaks water into hydrogen ions, electrons, and oxygen gas ($\ce{O_2}$). Carbon dioxide is used in the Calvin cycle to make glucose, glucose is the product of photosynthesis, and ATP is an energy carrier produced during photosynthesis, not a source of oxygen. So the oxygen released comes from water.

Answer:

A. Water