All states of matter exert pressure.

Explanation

**Step-by-Step Solution:**

1. **Understanding Pressure**: Pressure is defined as the force exerted per unit area. It is a fundamental concept in physics that applies to all states of matter: solids, liquids, and gases.

2. **Pressure in Solids**: Solids can exert pressure when a force is applied to them. For example, if you place a heavy object, like an iron box, on a spring, the weight of the box exerts a downward force on the spring, causing it to compress. This demonstrates that solids can exert pressure.

3. **Pressure in Liquids**: Liquids also exert pressure. When a liquid is contained in a vessel, the weight of the liquid above exerts pressure on the liquid below. This pressure increases with depth due to the weight of the liquid above.

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