**Category:** Plant Biology  
**Subtype:** Photosynthesis  
**Problem Description:** This problem involves calculating the amount of water needed for the light-dependent reactions of photosynthesis to produce a specific amount of glucose in C3 plants. Specifically, it asks how much water is required to produce 90 grams of glucose, given that all NADPH produced in the light phase is used in the dark phase to reduce APG to AlPG.