- A Maximize transpirational water loss while ambient humidity is highest
- B Fix CO2 at night as malate (stored in vacuole) to reduce water loss during day
- C Carry out the full light-dependent reactions of photosynthesis under starlight
- D Release oxygen generated by water-splitting at the oxygen-evolving complex
Correct answer: B. Fix CO2 at night as malate (stored in vacuole) to reduce water loss during day
Explanation: CAM plants (cacti, succulents): stomata open at night to fix CO2 (as malate). Stomata closed during hot day to prevent water loss. CO2 released from malate for Calvin cycle during day.
Concept context
Light reactions, the Calvin cycle, C3/C4/CAM pathways, photorespiration, and factors affecting the rate of photosynthesis. One of the highest-yield NEET chapters.