Answer: Fruit ripening and abscission.
- A Stem elongation driven by cell wall loosening at the apical meristem
- B Fruit ripening and abscission
- C Adventitious root formation at the cut ends of stem cuttings
- D Directional bending of shoots toward a unidirectional light source
Correct answer: B. Fruit ripening and abscission
Explanation: Ethylene is a gaseous hormone. It promotes fruit ripening and abscission (leaf/fruit drop).
Geometric growth (where both daughter cells keep dividing) produces this classic S-shaped curve: a slow lag phase, a rapid exponential phase, and a levelling-off stationary phase as nutrients or space become limiting - the same fundamental pattern seen in population growth.
Concept context
Phases of plant growth, the five classical plant hormones plus newer ones, photoperiodism, vernalization, and seed dormancy.