What are fluids ?

Explanation

### Step-by-Step Solution:

1. **Definition of Fluids**:
- Fluids are substances that can flow. This includes both liquids and gases.

2. **Examples of Fluids**:
- **Air**: When the wind blows, it moves and flows around objects, demonstrating the properties of a fluid.
- **Blood**: Blood moves through the circulatory system, flowing through veins and arteries, which also classifies it as a fluid.
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