Which molecule must enter the calvin cycle continually for the light-independent reactions to take place?
rubisco
rubp
3-pga
co2

The correct answer is option - CO₂.

Explanation:

The calvin cycle is the light independent reaction which is a series of chemical reaction in which a six carbon molecule RuBP incorporates CO₂ molecule to convert it into 3-PGA an organic material.

Carbon dioxide molecule is important to be incorporated into this process of the calvin cycle. Rest of the molecules are already present in the process.

Thus, the correct answer is option - carbon dioxide.