Three carbons of phosphoglyceric acid formed during carbon fixation are derived from

A. PEP + CO₂

B. RuBP

C. CO₂

D. RuBP + CO₂

Answer: Option D

Solution(By Examveda Team)

Three carbons of phosphoglyceric acid formed during carbon fixation are derived from RuBP + CO₂.
Phosphoglyceric acid (PGA), a 3-carbon organic acid formed during glycolysis is the first relatively stable compound formed in the Calvin cycle after the fixation of carbon dioxide in C₃ plants. The first product, an unstable 6-carbon compound, is formed when carbon dioxide combines with ribulose diphosphate.