The following are required for dark reaction

(I) H₂O

(II) CO₂

(III) ATP, NADPH+H⁺       

(IV) O₂

(I) H₂O, (II) CO₂, (III) ATP, NADPH+H⁺ are required for dark reaction.

Carbon dioxide is the primary carbon source required for the Calvin cycle. During the dark reaction, CO₂ is converted into organic molecules, such as glucose, through a series of chemical reactions.

ATP and NADPH, both produced during the light reaction (light-dependent reactions), provide the energy and reducing power, respectively, needed to fix carbon dioxide and synthesize carbohydrates in the Calvin cycle. ATP is the primary energy currency of the cell, and NADPH carries high-energy electrons required for the reduction of CO₂ to form carbohydrates.

H₂O is also required during Calvin cycle.