If salivary amylase is lacking in the saliva, which of the following events in the mouth cavity will be affected?

Options

A. Proteins breaking down into amino acids
B. Starch breaking down into sugars
C. Fats breaking down into fatty acids and glycerol
D. Absorption of vitamins

Explanation

### Step-by-Step Solution:

1. **Understand the Role of Salivary Amylase**: Salivary amylase is an enzyme found in saliva that initiates the digestion of carbohydrates, specifically starch. It breaks down starch into simpler sugars.

2. **Identify the Nutrients in the Options**: The question provides four options:
- A) Proteins breaking down into amino acids
- B) Starch breaking down into sugars
- C) Fats breaking down into fatty acids and glycerol
- D) Absorption of vitamins

3. **Analyze Each Option**:
- **Option A (Proteins)**: The breakdown of proteins into amino acids is primarily facilitated by different enzymes (like pepsin) in the stomach, not salivary amylase. Therefore, this process will not be affected.
- **Option B (Starch)**: Salivary amylase specifically targets starch and breaks it down into sugars. If salivary amylase is lacking, this process will be directly affected.
- **Option C (Fats)**: The digestion of fats into fatty acids and glycerol occurs mainly in the small intestine with the help of bile and lipases, not salivary amylase. Thus, this will not be affected.
- **Option D (Vitamins)**: The absorption of vitamins does not involve salivary amylase and occurs in the intestines, so this will also not be affected.

4. **Conclude the Correct Answer**: Since salivary amylase is responsible for breaking down starch into sugars, the absence of this enzyme will affect the process described in Option B. Therefore, the correct answer is **B) Starch breaking down into sugars**.