What is the role of water vapour in the formation of fog?

Explanation

**Step-by-Step Solution:**

1. **Understanding Water Vapour:** Water vapour is the gaseous form of water present in the atmosphere. It plays a significant role in weather and climate.

2. **Influence on Climate:** Water vapour affects climatic conditions by contributing to humidity and temperature regulation in the atmosphere.

3. **Condensation Process:** When the temperature drops, especially at night, water vapour in the air begins to cool down. This cooling causes the water vapour to condense.

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