Assertion: Nephrons are of two types: cortical and juxtamedullary according to their relative position in the cortex.
Reason, Juxtamedullary nephrons have short loop of Henle while cortical nephrons have long loop of Henle.

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, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that nephrons are of two types: cortical and juxtamedullary, based on their relative position in the cortex.

- **Cortical Nephrons**: These nephrons are primarily located in the cortex of the kidney. They make up about 85% of the total nephrons.
- **Juxtamedullary Nephrons**: These nephrons are located at the junction of the cortex and medulla and make up about 15% of the total nephrons.

### Step 2: Analyze the Reason
The reason provided states that juxtamedullary nephrons have a short loop of Henle, while cortical nephrons have a long loop of Henle.

- **Loop of Henle in Cortical Nephrons**: These nephrons have a short loop of Henle that does not extend deeply into the medulla.
- **Loop of Henle in Juxtamedullary Nephrons**: These nephrons have a long loop of Henle that extends deep into the medulla.

### Step 3: Determine the Truth of Assertion and Reason
- The assertion is **true** because it correctly identifies the two types of nephrons based on their location.
- The reason is **false** because it incorrectly states the lengths of the loops of Henle associated with each type of nephron.

### Conclusion
Since the assertion is true and the reason is false, the correct answer is that the assertion is true but the reason is false.

### Final Answer
The correct option is C: The assertion is true, but the reason is false.

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