What is common between the following pairs of substances
wood.and air

Explanation

To determine the common property between wood and air, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Substances**: The substances in question are wood and air.

2. **Understand the Concept of Insulators**:
- An insulator is a material that does not allow electric current to flow freely through it.
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