1. Which of these is NOT an output of the light- dependent reactions of photosynthesis? A. NADPH B. O_(2) C. ATP D. H_(2)O

The correct answer is D. $H_{2}O$.<br /><br />The light-dependent reactions of photosynthesis occur in the thylakoid membranes of the chloroplasts and involve the absorption of light energy by chlorophyll and other pigments. This energy is used to split water molecules ($H_{2}O$) into oxygen ($O_{2}$), protons, and electrons. The oxygen is released as a byproduct, while the electrons are used to generate ATP and NADPH, which are energy carriers used in the subsequent light-independent reactions of photosynthesis.<br /><br />Therefore, $H_{2}O$ is not an output of the light-dependent reactions of photosynthesis, but rather a reactant.