Consider two plants growing under identical CO2 concentrations but with different water availability: Plant A well-watered, Plant B water-limited. Analyze how water limitation may affect glucose production and O2 output in photosynthesis.

• A. Water limitation will increase glucose production in Plant B because limited water forces the plant to concentrate CO2 and accelerate photosynthesis, leading to greater O2 output per unit time than Plant A.
• B. Water availability only affects root growth and has no biochemical impact on photosynthesis; both plants will have identical glucose and O2 outputs regardless of hydration status.
• C. Plant B will produce the same glucose but will convert all produced oxygen into soil-bound oxides, so atmospheric O2 output remains unchanged while glucose accumulates internally without any difference from Plant A.
• D. Plant B (water-limited) will generally have reduced photosynthetic rates because water is required for photolysis and stomatal opening; this reduces electron donors and CO2 uptake, thus decreasing glucose production and O2 release compared with the well-watered Plant A.

Answer: (D)