In ABA signalling, the second messenger is

  1. calcium ions
  2. cyclic AMP
  3. water
  4. potassium ions
Answer

A) calcium ions

Ca²⁺ acts as a second messenger. AS & A Level Biology · Topic 14 Homeostasis · 14.2 Homeostasis in plants

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