Multiple choice

If CO2 concentration suddenly increases around the leaf, which one of the following events will occur?

  1. Stomata opens gradually

  2. Stomata opens suddenly

  3. Transpiration will not be affected

  4. Decrease in transpiration due to sudden closure of stomata

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When CO2 concentration rises around a leaf, it triggers a feedback mechanism - stomata partially close to reduce CO2 intake and conserve water. This decreases transpiration. Option D correctly describes this response. Options A and B are incorrect because high CO2 causes closure, not opening. Option C is incorrect because transpiration is affected through stomatal behavior.