Answer:
The three substances that enter into the Calvin cycle are:
1. carbon dioxide
2. ATP
3. NADPH
Step-by-step explanation:
In the Calvin cycle, which is part of the light-independent reactions of photosynthesis, carbon dioxide is used to synthesize glucose. ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate) are both energy-carrying molecules that provide the necessary energy and electrons for the synthesis of glucose from carbon dioxide. Conversely, oxygen is not a direct participant in the Calvin cycle, as it is produced as a byproduct of the light-dependent reactions of photosynthesis. Glucose, while a product of the Calvin cycle, is not an input into the cycle itself.