[A]: Homology is the similarity between organs of same animal based on common ancestory.
[R]: Analogy is seen in every organ system from fish to man

Options

A. (a) If both A and R are true and R is the correct explanation of A
B. (b) If both A and R are true but R is not the correct explanation of A
C. (c) If A is true and R is false
D. (d) If both A and R are false

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Homology is the similarity between organs of the same animal based on common ancestry."
- This means that homologous organs have similar structures due to evolution from a common ancestor, even if they serve different functions in different species.

2. **Identifying Examples of Homologous Organs**:
- An example of homologous organs is the forelimbs of humans and kangaroos.
- Both have similar bone structures (humerus, radius, ulna) but are adapted for different functions: humans use them for manipulation and walking, while kangaroos use them for jumping.

3. **Understanding the Reason**:
- The reason states that "Analogy is seen in every organ system from fish to man."
- This refers to analogous organs, which are different in structure but perform similar functions across different species.

4. **Identifying Examples of Analogous Organs**:
- An example of analogous organs is the gills of fish and the lungs of humans.
- Both serve the same function of respiration but are structurally different.

5. **Evaluating the Truth of the Statements**:
- Both the assertion and the reason are true statements.
- However, the reason does not directly explain the assertion; it discusses a different concept (analogy) rather than elaborating on homology.

6. **Conclusion**:
- Since both statements are true but the reason does not explain the assertion, the correct answer is that both assertion and reason are true, but the reason is not the correct explanation of the assertion.

### Final Answer:
- The correct answer is **B**: Both assertion and reason are true, but reason is not the correct explanation of assertion.