Which pair of plant hormones are primarily involved in growth regulation, with one promoting cell elongation and apical dominance and the other promoting cell division?

• A. Gibberellins and Abscisic acid
• B. Auxins and Cytokinins
• C. Auxins and Abscisic acid
• D. Ethylene and Brassinosteroids

Answer: (B)

Growth regulation in plants hinges on the actions and balance of two classic hormones. Auxin promotes cell elongation and keeps the main shoot dominant by suppressing growth of lateral buds. Cytokinin promotes cell division and supports tissue growth, often encouraging branching and shoot formation. Together, these hormones control how a plant grows by influencing both how much cells elongate and how readily cells divide. The pair that combines a signal for elongation and apical control with a signal for cell division best fits this description, because auxin provides the elongation and apical dominance and cytokinin drives division. The other hormones either don’t primarily drive cell division or regulate different processes like dormancy, ripening, or aging, so they don’t match as well.