What are plant hormones? Name the plant hormones responsible for the following:
`{:("(i) Growth of stem " ," (ii) Promotion of cell division"),("(iii) Inhibition of growth"," (iv) Elongation of cells"):}`

Explanation

### Step-by-Step Text Solution:

1. **Definition of Plant Hormones**:
Plant hormones, also known as phytohormones, are chemical messengers that regulate various physiological processes in plants, including growth, development, and responses to environmental stimuli. They are produced in one part of the plant and transported to other parts to elicit specific responses.

2. **Types of Plant Hormones**:
- **Auxins**: Involved in cell elongation and growth.
- **Cytokinins**: Promote cell division and differentiation.
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