Answer
Carbons enter the Calvin cycle as carbon dioxide molecules which are added to ribulose bisphosphate, and they leave as part of glyceraldehyde-3-phosphate. Please see the image.
Work Step by Step
This question is asking you to review the concept by doing some bookkeeping in order to see the forms that carbon takes in the Calvin cycle and how the total number of carbons into and out of the cycle balances.
