Stomata open when guard cells

  1. produce ABA
  2. become flaccid
  3. take up K⁺ ions and water, becoming turgid
  4. lose K⁺ ions and water
Answer

C) take up K⁺ ions and water, becoming turgid

Turgid guard cells curve apart. AS & A Level Biology · Topic 14 Homeostasis · 14.2 Homeostasis in plants

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