ABA causes stomata to close in water stress by

  1. causing K⁺ to leave guard cells so water follows
  2. increasing photosynthesis
  3. pumping water into guard cells
  4. causing K⁺ to enter guard cells
Answer

A) causing K⁺ to leave guard cells so water follows

Guard cells lose water. AS & A Level Biology · Topic 14 Homeostasis · 14.2 Homeostasis in plants

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