Assertion: Biceps and triceps are antagonistic muscles
Reason: The biceps flexes the arm and the tr4iceps straightens the arm.

Options

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

Explanation

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that "Biceps and triceps are antagonistic muscles." Antagonistic muscles are pairs of muscles that work against each other to create movement.

2. **Identifying the Muscles**: The biceps and triceps are both skeletal muscles located in the upper arm. The biceps is located on the front side of the upper arm, while the triceps is located on the back side.

3. **Function of Biceps**: The biceps muscle is responsible for flexing the arm at the elbow joint. When the biceps contracts, it pulls the forearm up towards the shoulder, causing the arm to bend.

4. **Function of Triceps**: The triceps muscle, on the other hand, is responsible for extending the arm at the elbow joint. When the triceps contracts, it straightens the arm by pulling the forearm down away from the shoulder.

5. **Relation Between Biceps and Triceps**: Since the biceps and triceps perform opposite actions (flexing and extending the arm), they are classified as antagonistic muscles. This means that when one muscle contracts, the other must relax to allow for smooth movement.

6. **Evaluating the Reason**: The reason states that "The biceps flexes the arm and the triceps straightens the arm." This statement is accurate as it correctly describes the functions of both muscles.

7. **Conclusion**: Both the assertion and reason are true, and the reason correctly explains why the assertion is true. Therefore, the correct answer is that both the assertion and the reason are true, and the reason is the correct explanation of the assertion.

### Final Answer:
Both the assertion and the reason are true, and the reason is the correct explanation of the assertion.

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