Which of the following statements is false?

Options

A. The breakdown of most of biomacromolecules occurs in duodenum
B. Simple substances (digested foods) are absorbed in the jejunum and ileum
C. Very significant digestive activity occurs in large intestine
D. Undigested and unabsorbed substances are passed on to the large intestine

Answer

To determine which statement is false, we need to analyze each option provided regarding digestion and absorption in the human digestive system.

### Step-by-Step Solution:

1. **Understanding the Role of the Duodenum**:
- The duodenum is the first part of the small intestine and is crucial for digestion. It is where most of the enzymatic breakdown of food occurs, particularly for biomacromolecules like proteins, fats, and carbohydrates.
- **Hint**: Remember that the duodenum is the primary site for the initial digestion of food.

2. **Analyzing the First Statement**:
- The statement claims that "the breakdown of most of the biomacromolecules occurs in the duodenum."
- This is true, as the duodenum receives digestive enzymes from the pancreas and bile from the liver, facilitating the breakdown of biomacromolecules.
- **Hint**: Focus on the function of the duodenum in digestion.

3. **Analyzing the Second Statement**:
- The second statement mentions that "simple substances are absorbed in the duodenum."
- This is also true. The duodenum is involved in the absorption of simple sugars, amino acids, and fatty acids after they have been broken down.
- **Hint**: Consider the absorption capabilities of the small intestine.

4. **Analyzing the Third Statement**:
- The third statement suggests that "very significant digestive activity occurs in the large intestine."
- This statement is misleading. While the large intestine does play a role in the absorption of water and electrolytes, most digestion occurs in the small intestine, particularly in the duodenum and jejunum.
- **Hint**: Recall the primary functions of the large intestine compared to the small intestine.

5. **Analyzing the Fourth Statement**:
- The fourth statement indicates that "undigested food particles pass into the large intestine."
- This is true. The large intestine primarily handles undigested food material and is involved in the formation of feces.
- **Hint**: Think about the role of the large intestine in waste management.

### Conclusion:
Based on the analysis, the false statement is the one that claims "very significant digestive activity occurs in the large intestine." Most digestion occurs in the small intestine, particularly in the duodenum.

### Final Answer:
The false statement is: "Very significant digestive activity occurs in the large intestine."