Assertion : Isogametes are formed in majority of sexually reproducing organisms.
Reason : Morphologically distinct type of gametes are called isogametes.

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

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that "isogametes are formed in the majority of sexually reproducing organisms."
- To evaluate this, we need to define isogametes. Isogametes are gametes that are morphologically similar or identical.

2. **Understanding the Reason:**
- The reason provided is that "morphologically distinct type of gametes are called isogametes."
- This statement is incorrect because morphologically distinct gametes are known as anisogametes, not isogametes.

3. **Analyzing the Types of Gametes:**
- In sexually reproducing organisms, there are typically two types of gametes:
- **Heterogametes (or Anisogametes):** These are morphologically distinct gametes (e.g., sperm and egg).
- **Isogametes:** These are morphologically similar gametes and are usually found in organisms that reproduce asexually.

4. **Conclusion on the Assertion and Reason:**
- Since the assertion is incorrect (isogametes are not formed in the majority of sexually reproducing organisms) and the reason is also incorrect (the definition of isogametes is wrong), we conclude that both the assertion and the reason are false.

5. **Final Answer:**
- Therefore, the correct option is that both the assertion and reason are false.