15. Which hormones has been shown to trigger stem elongation, fruit growth, and seed germination?
(A) auxin
(B) cytokinin
(C) gibberellin
(D) abscisic acid
(E) ethylene

Option (A) auxin is not the correct answer because, while auxins are important plant hormones involved in various growth processes, their primary roles are in cell elongation, apical dominance, and root development rather than specifically triggering stem elongation, fruit growth, and seed germination as prominently as gibberellins do.

Gibberellins are particularly known for their role in promoting:

• Stem elongation: They help cells grow longer.
• Fruit growth: They influence fruit development and size.
• Seed germination: They help break dormancy and promote the growth of seedlings.

Auxins do contribute to growth and development, but gibberellins are more directly associated with these specific processes.