Multiple choice

When the stomata in a leaf closes, ________________.

  1. carbon dioxide in the air spaces in the leaf decreases

  2. oxygen in the air spaces in the leaf increases

  3. C3 plants carry on photorespiration using oxygen and produce PGA and carbon dioxide

  4. all photosystems as well as photorespiration come to a halt

  5. 1, 2 and 3 are correct
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

When stomata close, gas exchange stops, leading to a decrease in CO2, an increase in O2 (due to light reactions), and the initiation of photorespiration in C3 plants.

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