What are herbicides? Give one example.

Explanation

### Step-by-Step Solution:

1. **Definition of Herbicides**:
- Herbicides are chemical substances specifically designed to kill unwanted plants, commonly known as weeds. They are used in agriculture to protect crops by eliminating competition for nutrients, water, and sunlight.

2. **Purpose of Herbicides**:
- The primary purpose of herbicides is to control or eliminate unwanted vegetation that can hinder the growth of desired crops. By using herbicides, farmers can improve crop yield and maintain the health of their agricultural fields.

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