_____impart freshness and sparkling appearance to water.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks what substances or elements give water its freshness and sparkling appearance.

2. **Identifying Key Elements**: We need to think about what can be found in water that contributes to its qualities.

3. **Considering Dissolved Gases**: One of the main contributors to the freshness and sparkling appearance of water is the presence of dissolved gases.

4. **Listing the Gases**: The primary gases that are dissolved in water and contribute to its characteristics are oxygen (O2) and carbon dioxide (CO2).

5. **Conclusion**: Therefore, the answer to the question is that "dissolved gases like oxygen and carbon dioxide impart freshness and sparkling appearance to water."

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