[A]: Each testis is attached to the abdominal wall by a ligament and under testosterone influence it is drawn into the scrotum during development.
(R]: Leydig or interstitial cells secrete androgens most potent being testosterone

Options

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

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that each testis is attached to the abdominal wall by a ligament and that under the influence of testosterone, it is drawn into the scrotum during development. This is a true statement as the testes are indeed connected to the abdominal wall via the spermatic cord and descend into the scrotum influenced by testosterone.

2. **Understanding the Reason**: The reason provided is that Leydig or interstitial cells secrete androgens, with testosterone being the most potent. This statement is also true, as Leydig cells are responsible for the production of testosterone, which is crucial for male reproductive development.

3. **Analyzing the Relationship**: While both the assertion and the reason are true, we need to determine if the reason explains the assertion. The assertion discusses the descent of the testes into the scrotum, while the reason discusses the secretion of testosterone by Leydig cells. The secretion of testosterone is indeed important for the descent, but the reason does not directly explain how the attachment to the abdominal wall and the descent into the scrotum occur.

4. **Conclusion**: Since both the assertion and the reason are true, but the reason does not serve as a correct explanation for the assertion, the correct option is that both assertion and reason are true, but the reason is not the correct explanation of the assertion.

### Final Answer:
Both assertion and reason are true, but reason is not the correct explanation of assertion.

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