correct answer:
"to synthesize a simple sugar (g3p) from carbon dioxide"
The main purpose of the Calvin cycle is two synthesize simple sugars from carbon dioxide. Per cycle, 6 G3P are created. Five of those continue the cycle again while one is used to the synthesizing of glucose, which will be the plant's energy source for many other reactions. The process of adding more carbon atoms from carbon dioxide to the existant carbons of the cycle is called Carbon fixation.