Answer:
Directly light is not required in Calvin cycle so called as dark reaction.
Step-by-step explanation:
Photosynthesis is a biochemical process in which light energy is utilized to produce organic compounds like carbohydrates from inorganic compounds like carbon dioxide and water. This process is completed on two steps mechanism. In the first step, directly light energy is required so-called as a light reaction while in the second step ATP and NADPH are required and thus light is not directly involved so-called as a dark reaction or light-independent reaction or Calvin cycle.