The main process that occurs in the dark reaction in photosynthesis is:

Explanation

The main process that occurs in the dark reaction (also known as the Calvin Cycle) in photosynthesis is the synthesis of glucose. The dark reaction takes place in the stroma of chloroplasts and does not directly require light. It follows the light-dependent reactions (such as photosystem I and II) that capture and convert light energy into chemical energy in the form of ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate). In the Calvin Cycle, the primary goal is to use the ATP and NADPH produced during the light-dependent reactions to convert carbon dioxide (CO2) into glucose. The key steps of the Calvin Cycle include carbon fixation, reduction, and regeneration of the starting molecule (RuBP, ribulose-1,5-bisphosphate). The final product is glucose, which can be used by the plant for energy and other metabolic processes.