What are insulators? Give examples.

Explanation

**Step-by-Step Solution:**

1. **Definition of Insulators**:
- Insulators are materials that do not allow electricity to flow through them easily. They have high resistance to the flow of electric current.

2. **Characteristics of Insulators**:
- Insulators have very few free electrons. Free electrons are necessary for the conduction of electricity. The lack of these free electrons means that electrical current cannot pass through these materials.

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