The effect of apical dominance can be overcome by which of the following hormone ?

Options

A. IAA
B. Ethylene
C. Gibberellin
D. Cytokinin

Explanation

### Step-by-Step Solution:

1. **Understanding Apical Dominance**: Apical dominance is a phenomenon in plants where the main central stem (apical bud) grows more strongly than the other side shoots (lateral buds). This is primarily regulated by plant hormones.

2. **Identifying the Hormones**: The question provides four options: IAA (Indole-3-acetic acid), ethylene, gibberellin, and cytokinin. We need to determine which of these hormones can overcome apical dominance.

3. **Role of Auxins**: Auxins, such as IAA, are known to promote apical dominance. They encourage the growth of the apical bud while inhibiting the growth of lateral buds.

4. **Cytokinins Function**: Cytokinins have an opposite effect to auxins. They promote the growth of lateral buds and can help overcome apical dominance. When applied to lateral buds, cytokinins stimulate their growth even in the presence of the apical bud.

5. **Conclusion**: Since cytokinins counteract the effects of auxins and promote lateral bud growth, they are the hormone that can overcome apical dominance.

6. **Final Answer**: The effect of apical dominance can be overcome by the hormone **cytokinin**.