Identify the stages: The three stages of the Calvin Cycle are: 1) Carbon fixation, where CO2 is incorporated into an organic molecule, 2) Reduction phase, where ATP and NADPH are used to convert 3-phosphoglycerate into glyceraldehyde-3-phosphate (G3P), and 3) Regeneration of RuBP, where G3P is used to regenerate RuBP, allowing the cycle to continue.