Assertion : Stomach and intestine of our body has columnar epithelium
Reason : Columnar epithelium helps is secretion and absorption.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false

Explanation

To solve the question regarding the assertion and reason provided, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
The assertion states: "Stomach and intestine of our body has columnar epithelium."
- The stomach and intestines are indeed lined with a type of epithelium known as columnar epithelium. This is a well-established fact in human anatomy and physiology.

### Step 2: Analyze the Reason
The reason states: "Columnar epithelium helps in secretion and absorption."
- Columnar epithelium is specialized for functions such as secretion and absorption. In the digestive tract, this type of epithelium plays a crucial role in the absorption of nutrients and the secretion of digestive enzymes and mucus.

### Step 3: Determine the Relationship Between Assertion and Reason
- Both the assertion and the reason are true. Furthermore, the reason provides a correct explanation for the assertion. The presence of columnar epithelium in the stomach and intestines is indeed related to its functions of secretion and absorption.

### Conclusion
Based on the analysis:
- Both the assertion and the reason are true, and the reason is the correct explanation of the assertion.

### Final Answer
The correct option is: "Both assertion and reason are true; the reason is the correct explanation of the assertion."

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