- A Cell elongation and phototropism
- B Cell division at root tip
- C Leaf senescence
- D Stomatal closure
Correct answer: A. Cell elongation and phototropism
Explanation: Auxin (IAA) promotes cell elongation in stems and is responsible for phototropism (bending toward light).
Concept context
Phases of plant growth, the five classical plant hormones plus newer ones, photoperiodism, vernalization, and seed dormancy.