A. Animals are either unisexual or bisexual
R. Most of the bisexual animals reproduce by cross-fertilization.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion
B. It both Assertion & Reason are true but the reason is not the correct explanation of the assertion
C. If Assertion is true statement but Reason is false
D. If both Assertion and Reason are false statements

Answer

To solve the question, we need to analyze the assertion and the reason provided:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Animals are either unisexual or bisexual."
- **Unisexual organisms** are those that have either male or female reproductive organs, meaning they belong to one sex only. Examples include humans, where males and females are separate individuals.
- **Bisexual organisms** possess both male and female reproductive organs within the same individual. An example is the earthworm.

2. **Evaluating the Assertion**:
- The assertion is true because animals can indeed be classified as unisexual or bisexual based on their reproductive structures.

3. **Understanding the Reason**:
- The reason states that "Most of the bisexual animals reproduce by cross-fertilization."
- Cross-fertilization occurs when gametes from different individuals combine to form a zygote. In bisexual organisms like earthworms, this is common because they have both male and female organs but often do not self-fertilize.

4. **Evaluating the Reason**:
- The reason is also true. Many bisexual organisms do reproduce through cross-fertilization, as it increases genetic diversity.

5. **Analyzing the Relationship**:
- While both the assertion and the reason are true, the reason does not explain the assertion. The assertion is a classification of animals, while the reason describes a reproductive strategy of some bisexual organisms.

6. **Conclusion**:
- Since both statements are true but the reason does not correctly explain the assertion, the correct option is:
- **Option 2**: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.