Assertion(A): Arteries do not collapse, but veins collapse when they are cut through.
Reason (R): Arteries do not have valves whereas veins have valves.

Options

A. Both A and Rare true and R is the cor- rect explanation for A.
B. Both A and R are true, but R is not the correct explanation for A.
C. A is true and R is false.
D. A is false and R is true.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion (A)**:
- The assertion states that "Arteries do not collapse, but veins collapse when they are cut through."
- This is true because arteries have thick, elastic walls that maintain their shape and structure even under pressure, while veins have thinner walls that can collapse when not filled with blood.

2. **Understanding the Reason (R)**:
- The reason states that "Arteries do not have valves whereas veins have valves."
- This statement is also true. Arteries do not have valves because blood is pumped through them at high pressure from the heart, which prevents backflow. Veins, on the other hand, have valves to prevent the backflow of blood as it returns to the heart at lower pressure.

3. **Analyzing the Relationship**:
- While both the assertion and reason are true, the reason does not correctly explain the assertion. The reason focuses on the presence of valves, which is not the primary reason for the collapse of veins. The collapse of veins is primarily due to their thinner walls and lower pressure of blood flow.

4. **Conclusion**:
- Therefore, the correct conclusion is that both the assertion and reason are true, but the reason is not the correct explanation of the assertion.

5. **Final Answer**:
- The correct option is: "Both the assertion and reason are true, but the reason is not the correct explanation of the assertion."

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