Which of the following pair has homologous organs ?

Options

A. Pectoral fins of a fish and forelimbs of a horse
B. Wings of a bat and wings of cockroach
C. Air sac of fistf and lungs of frog
D. Wings of a bird and wings of a butterfly

Explanation

To determine which of the following pairs has homologous organs, we need to understand the definitions and characteristics of homologous and analogous organs.

### Step-by-Step Solution:

1. **Define Homologous Organs**:
Homologous organs are those that have a similar origin or structure but serve different functions. They arise from a common ancestor and are found in related species.

2. **Define Analogous Organs**:
Analogous organs, on the other hand, are those that serve similar functions but do not share a common origin. They arise in unrelated species and are structurally different.

3. **Analyze the Given Pairs**:
- **Pectoral fins of fish and forelimbs of horse**: Both are limbs of vertebrates, indicating a common ancestry. The pectoral fins are used for swimming, while the forelimbs of a horse are used for running. Despite their different functions, they share a similar structural origin.

- **Wings of birds and wings of butterfly**: Both serve the function of flying but come from different evolutionary backgrounds. Thus, they are analogous organs.

- **Air sac of fish and lungs of frogs**: Both are involved in respiration but have different structures and origins, making them analogous organs.

- **Wings of bat and wings of cockroach**: Both serve the function of flying but are structurally different and do not share a common ancestor, hence they are analogous organs.

4. **Conclusion**:
The pair that has homologous organs is the **pectoral fins of fish and forelimbs of horse**. They share a common ancestral origin and have different functions.

### Final Answer:
The homologous organs pair is **pectoral fins of fish and forelimbs of horse**.

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