Stomata must open to

  1. let oxygen in for respiration only
  2. let carbon dioxide in for photosynthesis
  3. absorb light
  4. stop transpiration
Answer

B) let carbon dioxide in for photosynthesis

The trade-off is CO₂ gain vs water loss. AS & A Level Biology · Topic 14 Homeostasis · 14.2 Homeostasis in plants

Biology MCQ · More A Level Biology: Homeostasis MCQs · Practise