AIIMS 2019 Biology Plant Hormones MCQ Question

Abscisic acid (ABA) is a plant hormone that plays a crucial role in inhibiting morphogenesis, particularly under stress conditions, by promoting seed dormancy and preventing germination. In contrast, 2,4-D (option B) is a synthetic auxin that promotes cell elongation and growth, jasmonic acid (option C) is involved in stress responses and defense mechanisms, and indole-3-butyric acid (IBA, option D) is a rooting hormone that encourages root development. Thus, while ABA acts to suppress growth and morphogenetic processes, the other options facilitate various aspects of plant growth and development.