Which of the following is a plant hormone responsible for promoting cell elongation and growth?

Step 1: Analyze the question We need the plant hormone mainly responsible for promoting cell elongation and growth.

Step 2: Review each hormone

• A. Abscisic acid (ABA): A growth inhibitor. It promotes seed and bud dormancy, closes stomata during water stress, and is involved in leaf fall. It does not promote elongation.
• B. Gibberellins: Promote stem elongation and cell growth. They also break seed dormancy, stimulate germination, and cause bolting in some plants. They are famous for making dwarf plants grow tall.
• C. Ethylene: A gaseous hormone that promotes fruit ripening, leaf abscission, and senescence. It generally inhibits elongation.
• D. Cytokinins: Promote cell division (cytokinesis), delay leaf aging, and encourage lateral bud growth. Their main role is division, not elongation.

Auxins would also be a strong answer for cell elongation, but they are not among the options. Of the choices given, gibberellins are the best fit for promoting elongation and growth.

Answer: B. Gibberellins

Exam tip: Remember the key roles this way:

• Gibberellins = Growth in height (stem elongation)
• Cytokinins = Cell division
• Ethylene = Eripening
• ABA = Against growth (stress and dormancy)