AIIMS 2019 Botany C₃ and C₄ Pathways MCQ Question

In C₃ plants, the C₃ cycle, also known as the Calvin cycle, occurs in the mesophyll cells where CO₂ is fixed into a 3-carbon compound (3-phosphoglycerate) using ribulose bisphosphate (RuBP) and the enzyme RuBisCO. In C₄ plants, the initial fixation of CO₂ occurs in the mesophyll cells, forming a 4-carbon compound (oxaloacetate), which is then transported to the bundle sheath cells where the C₃ cycle takes place, allowing for efficient carbon fixation under high light and temperature conditions. Option B is incorrect because it misplaces the locations of the C₃ cycle in both plant types, while options C and D are not applicable as they provide no relevant information.