How does saliva act in body defence?

Explanation

### Step-by-Step Solution:

1. **Introduction to Saliva**: Saliva is a fluid produced by salivary glands in the mouth. It plays a crucial role in digestion and also serves various functions in the body’s defense mechanisms.

2. **Presence of Bicarbonate Ions**: One of the key components of saliva is bicarbonate ions. These ions are essential for maintaining the pH balance in the mouth.

3. **Neutralization of Acids**: The bicarbonate ions in saliva help to neutralize acids present in food. This is important because excessive acidity can harm the tissues in the mouth and create an environment conducive to bacterial growth.

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