Question

In $C_3$ plants, the first stable product of photosynthesis during the dark reaction is:

• A. Oxaloacetic acid
• B. 3-phosphoglyceric acid
• C. Phosphoglyceraldehyde
• D. Malic acid

Answer 1

The correct option is B 3-phosphoglyceric acid

3-phosphoglyceric acid, is a 3 carbon compound that is first formed in the $C_3$ cycle. It is then converted to glyceraldehyde-3-phosphate.
Oxaloacetic acid, is a 4 carbon compound that is first formed in the $C_4$ cycle. It is then converted to malic acid.