Question

Respectively in $C_3$ and $C_4$ plants whether photorespiration would be present at low $C{O}_2$ concentration.

• A. Negligible, Negligible
• B. High, High
• C. Negligible, High
• D. High, Negligible

Answer 1

The correct option is B High, High

When availability of carbon dioxide is low, the plants undergo photorespiration.

Hence it increases when carbon dioxide levels are low.

In this process the enzyme RubisCO starts acting on oxygen instead of carbon dioxide and this turns out to be a wasteful process.

So the correct answer is 'High, High'.