……..…….is the purest form of natural water.

Answer

**Step-by-Step Text Solution:**

1. **Understanding Natural Water Sources**: Natural water comes from various sources such as rivers, lakes, ponds, and the ocean. Each of these sources has different levels of purity due to the presence of minerals, pollutants, and other substances.

2. **Identifying the Types of Natural Water**: The main types of natural water include:
- River water
- Sea water
- Pond water
- Lake water
- Rainwater

3. **Evaluating Purity**: Among these types, we need to evaluate which one is the purest. River, sea, pond, and lake water can contain various impurities and contaminants, including sediments, microorganisms, and chemicals.

4. **Understanding Rainwater Formation**: Rainwater is formed through the process of evaporation and condensation. Water from natural sources evaporates due to sunlight, turning into water vapor. This vapor rises into the atmosphere, where it cools and condenses to form clouds.

5. **Rainwater as the Purest Form**: When rain falls, it is generally free from the impurities found in other natural water sources. This is because it has undergone the process of evaporation, which leaves behind many contaminants. Therefore, rainwater is considered the purest form of natural water.

6. **Conclusion**: Based on the evaluation of the different types of natural water and the process of rainwater formation, we conclude that the answer to the question is: **Rainwater is the purest form of natural water.**

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