Phosphorus is important for which process in vines?

• A. Photosynthesis
• B. Nitrogen fixation
• C. Chlorophyll metabolism
• D. Sugar production

Answer: (A)

Phosphorus fuels energy transfer in plants, which is why it is so closely linked to photosynthesis. It’s a core part of ATP and other high‑energy phosphate compounds that store and supply the energy needed for the light‑driven reactions and the Calvin cycle. In grapevines, this energy is what powers the conversion of carbon dioxide into sugars during photosynthesis, so phosphorus directly supports this process.

Nitrogen fixation isn’t a vine process, and chlorophyll metabolism relies more on magnesium and pigment biosynthesis than on phosphorus itself. Sugar production is the outcome of photosynthesis, not the process that phosphorus directly powers. So the best answer is photosynthesis.