Which of the following is a stress hormone in plants?

✅Explanation:
Abscisic Acid (ABA) is a plant hormone known as a stress hormone. It plays a role in various plant responses to environmental stresses, such as drought, high salinity, and cold temperatures. ABA helps plants conserve water by promoting stomatal closure (closing of tiny pores in leaves) and reducing growth.

📌📌Other Options:
-IAA (Indole-3-acetic Acid): This is another form of auxin, a growth hormone.
-Ethylene: Ethylene is another plant hormone with diverse effects, including fruit ripening, leaf senescence, and responses to stress. It can interact with stress signaling pathways.

🔑Key Points:
-It is called a stress hormone because its synthesis is stimulated by environmental stresses like drought, water logging, etc.

• It induces various responses in plants against stress conditions:
-increases the tolerance of plants toward various stresses
-induces the closure of the stomata during water stress
-promotes seed dormancy 
-helps seeds withstand desiccation
-important role in the growth and modification of root during nitrogen deficiency and drought
-involved in the synthesis of dehydrins, osmoprotectants and protective proteins
-inducing dormancy in plants at the end of the growing season
-promotes abscission of leaves, fruits, and flowers
-plant growth inhibitor and regulates abscission and dormancy