Which hormone is associated with promoting plant growth by stimulating cell division?

Cytokinin is indeed the hormone associated with promoting plant growth by stimulating cell division. It primarily functions by promoting the growth and development of lateral buds, which can lead to bushier plant growth. Cytokinins are known to regulate various aspects of plant growth, including the division and differentiation of cells, which is crucial for the development of new tissues. They work in conjunction with auxins, another plant hormone, to ensure that growth is coordinated and that the plant develops properly in both structure and function.

In addition to promoting cell division, cytokinins also play a significant role in delaying senescence (aging) in leaves, thereby prolonging their life and functionality. This is particularly important for the overall health and productivity of plants, as it allows for better photosynthesis and nutrient storage.

Other hormones also influence plant growth but do so in different ways. Ethylene is primarily involved in the regulation of fruit ripening and responses to stress, while gibberellins promote stem elongation and seed germination, and auxins are critical for cell elongation and directional growth (phototropism and gravitropism). However, the specific function of stimulating cell division distinctly points to cytokinins as the correct answer.