Increase in the height of the plant is due to

Options

A. Auxins
B. Cytokinins
C. Gibberellins
D. Ethylene

Answer

To determine the hormone responsible for the increase in the height of a plant, we can analyze the functions of the different plant hormones mentioned in the question.

### Step-by-Step Solution:

1. **Understanding Plant Hormones**:
- There are several plant hormones that play different roles in plant growth and development. The main hormones to consider in this context are auxin, cytokinin, gibberellin, and ethylene.

2. **Analyzing Auxin**:
- Auxin is known for promoting apical dominance, which means it helps the main shoot grow taller while inhibiting the growth of lateral buds. However, it is not primarily responsible for increasing overall height.

3. **Analyzing Cytokinin**:
- Cytokinins are involved in promoting cell division and can influence the growth of shoots and roots. They play a role in the growth process but are not the primary hormones for height increase.

4. **Analyzing Ethylene**:
- Ethylene is a hormone that is primarily involved in fruit ripening and the regulation of other processes such as leaf abscission. It does not contribute to the increase in plant height.

5. **Analyzing Gibberellin**:
- Gibberellins are known for promoting stem elongation, seed germination, and flowering. They are specifically responsible for increasing the height of the plant by promoting cell elongation and division.

6. **Conclusion**:
- Based on the functions of these hormones, the hormone responsible for the increase in the height of the plant is **gibberellin**.

### Final Answer:
The increase in the height of the plant is due to **gibberellin**.

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