Which of the following. Options about sites of digestion is CORRECT ?

Options

A.
B.
C.
D.

Answer

To solve the question regarding the correct statements about the sites of digestion, we will analyze each option step by step.

### Step 1: Analyze Carbohydrate Digestion
- **Mouth**: Digestion of carbohydrates begins in the mouth where salivary amylase breaks down starch into disaccharides.
- **Stomach**: There is no significant digestion of carbohydrates in the stomach. The acidic environment and lack of amylase activity halt carbohydrate digestion.
- **Small Intestine**: The digestion of carbohydrates continues in the small intestine with the help of enzymes from the pancreas and intestinal lining.

**Conclusion**: Carbohydrate digestion primarily occurs in the mouth and small intestine, but not in the stomach.

### Step 2: Analyze Protein Digestion
- **Mouth**: No digestion of proteins occurs in the mouth.
- **Stomach**: Protein digestion begins in the stomach where pepsin (activated from pepsinogen) breaks down proteins into smaller peptides.
- **Small Intestine**: The digestion of proteins continues in the small intestine with proteases from pancreatic juice.

**Conclusion**: Protein digestion starts in the stomach and continues in the small intestine.

### Step 3: Analyze Fat Digestion
- **Mouth**: Some initial digestion of fats occurs in the mouth due to lingual lipase, but it is minimal.
- **Stomach**: Some digestion of fats occurs in the stomach due to gastric lipase, but again, it is limited.
- **Small Intestine**: The majority of fat digestion occurs in the small intestine with the help of bile and pancreatic lipase.

**Conclusion**: While some fat digestion occurs in the mouth and stomach, the primary site is the small intestine.

### Step 4: Analyze Nucleic Acid Digestion
- **Mouth**: There is no digestion of nucleic acids in the mouth.
- **Stomach**: Nucleic acid digestion does not occur in the stomach.
- **Small Intestine**: The digestion of nucleic acids occurs in the small intestine where nucleases break down nucleic acids into nucleotides.

**Conclusion**: Nucleic acid digestion primarily occurs in the small intestine.

### Final Answer
Based on the analysis:
- The correct option regarding the sites of digestion is **Option 4**: Digestion of Nucleic Acid mainly happens in the small intestine.