Assertion. Protandry and protogyny ensure cross fertilization.
Reason . Cross fertilization introduces variation in progeny.

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 assertion and reason question, we will analyze both statements step by step.

### Step 1: Understanding the Assertion
The assertion states that "Protandry and protogyny ensure cross-fertilization."

- **Protandry** refers to a condition where the male reproductive organs mature before the female reproductive organs in a hermaphroditic organism. This means that the organism can produce sperm before it can produce eggs, which encourages mating with another individual.
- **Protogyny** is the opposite; it refers to a condition where the female reproductive organs mature before the male reproductive organs. This allows the organism to produce eggs before it can produce sperm, also promoting cross-fertilization.

**Conclusion for Step 1**: Both protandry and protogyny facilitate cross-fertilization by ensuring that an organism can mate with another individual rather than self-fertilizing.

### Step 2: Understanding the Reason
The reason states that "Cross fertilization introduces variation in progeny."

- Cross-fertilization occurs when gametes from two different individuals fuse to form a zygote. This process introduces genetic variation because the offspring inherit genetic material from two different parents, leading to a diverse genetic makeup.

**Conclusion for Step 2**: The reason is correct; cross-fertilization does indeed lead to variation in the progeny.

### Step 3: Analyzing the Relationship Between the Assertion and Reason
Now we need to determine if the reason is the correct explanation for the assertion.

- While both statements are true, the reason does not directly explain why protandry and protogyny ensure cross-fertilization. The assertion focuses on the reproductive strategies (protandry and protogyny) that promote cross-fertilization, while the reason discusses the outcome of cross-fertilization (variation in progeny).

### Final Conclusion
Both the assertion and reason are true, but the reason is not the correct explanation for the assertion.

**Answer**: Both assertion and reason are true, but the reason is not the correct explanation for the assertion.