Answer: Auxin.
- A Ethylene
- B Cytokinin
- C Auxin
- D Abscisic acid
Correct answer: C. Auxin
Explanation: Auxin sprays can make ovaries develop into fruit without fertilisation, giving seedless (parthenocarpic) fruits.
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.