Saliva is active in the medium

Options

A. acidic
B. basic
C. neutral
D. All of these

Explanation

**Step-by-Step Solution:**

1. **Understanding Saliva Composition**: Saliva is primarily composed of about 99% water, making it a liquid medium. This is important because the activity of saliva is influenced by its state (liquid) rather than being solid or gas.

2. **Identifying the Medium**: The question asks about the activity of saliva in terms of pH levels: acidic, basic, or neutral. Saliva can exist in different pH conditions depending on various factors, such as the food consumed or the state of hunger.

3. **Saliva pH Levels**:
- **Acidic Medium**: When a person is hungry, the saliva can become acidic.
- **Basic Medium**: When consuming acidic foods, saliva works to neutralize the acidity, thus becoming basic.
- **Neutral Medium**: In some cases, saliva can be neutral, especially when the diet is balanced.

4. **Conclusion**: Since saliva can function in all three pH conditions (acidic, basic, and neutral) depending on the circumstances, the correct answer to the question is that saliva is active in all of these mediums.

5. **Final Answer**: Therefore, the correct option is **4. All of these**.

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