To what group of biomolecules do the main products of the dark stage belong?

• A. Monosaccharides
• B. Lipids
• C. Polysaccharides
• D. Carbohydrates

Answer: (D)

In the dark stage, CO2 is fixed into triose phosphates, which are three-carbon sugars. These compounds are carbohydrates, the broad family that includes simple sugars and the larger sugar polymers formed later. The immediate products are simple sugars, so they fit under carbohydrates as the correct group. They aren’t lipids, and they aren’t yet polysaccharides, though they can be further converted into larger carbohydrate molecules like starch or sucrose.