Final answer:
The hormone not working correctly if a plant is a dwarf plant is gibberellin, which is essential for stem elongation and breaking dormancy in seeds and buds.
Step-by-step explanation:
If a plant is a dwarf plant, it typically has a hormonal issue related to the production of gibberellins. Gibberellins are plant hormones that play a vital role in promoting stem elongation and thus overall plant growth. In dwarf plants, the concentration of gibberellins is often unusually low, which results in the shorter stature of these plants. Apart from their role in stem growth, gibberellins also help in breaking the dormancy of seeds and buds, signaling them to germinate or open.