Question

Assertion : $C_4$ photosynthetic pathway is more efficient than the $C_3$ pathway.
Reason : Photorespiration is suppressed in $C_4$ plants.

• A. Both assertion and reason are true, and reason is the correct explanation.
• B. Assertion and reason are false.
• C. Assertion is true, but the reason is false.
• D. Both assertion and reason are true, but the reason is not the correct explanation.

Answer 1

The correct option is A Both assertion and reason are true, and reason is the correct explanation.

$C_4$ pathway/Hatch and Slack pathway ensures the Calvin cycle to be operated only in a bundle sheath cell. It is an adaptation to photorespiratory loss. Therefore, $C_4$ plants are adapted to photorespiratory loss, by having a mechanism that increases the concentration of ${\mathrm{CO}}_2$ at the enzyme site.