Assertion (A): The secretory phase in the human menstrual cycle is also called the luteal phase.
Reason (R): During the luteal phase development of corpus luteum and secretion of progesterone occurs.

Options

A. Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion(A).
B. Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
C. Assertion (A) is true but reason (R) is false.
D. Assertion (A) is false but reason (R) is true.

Explanation

To analyze the assertion and reason provided in the question, we can break it down into a step-by-step solution:

### Step-by-Step Solution:

1. **Understanding the Menstrual Cycle Phases**:
- The human menstrual cycle consists of three main phases: the menstrual phase, the follicular phase, and the luteal phase.

2. **Identifying the Luteal Phase**:
- The luteal phase occurs after ovulation, which typically happens around the 14th day of the cycle. This phase is characterized by the transformation of the ruptured follicle into the corpus luteum.

3. **Defining the Secretory Phase**:
- The secretory phase is another name for the luteal phase. During this time, the endometrium (lining of the uterus) becomes more vascular and glandular in preparation for a potential implantation of a fertilized egg.

4. **Role of Corpus Luteum**:
- After ovulation, the ruptured follicle develops into the corpus luteum. This structure is crucial as it secretes hormones, particularly progesterone, which helps maintain the uterine lining.

5. **Hormonal Secretion**:
- The secretion of progesterone is essential during the luteal phase (or secretory phase) as it prepares the endometrium for possible implantation of an embryo.

6. **Evaluating the Assertion and Reason**:
- The assertion states that the secretory phase is also called the luteal phase, which is correct.
- The reason states that during the luteal phase, the development of the corpus luteum and secretion of progesterone occurs, which is also correct.

7. **Conclusion**:
- Both the assertion and reason are true, and the reason correctly explains the assertion.

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

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