Which of the following is a pair of homologous organs?

Options

A. Pectoral fin of fish and fore-limb of horse
B. Wings of grasshopper and wings of crow
C. Lungs of rabbit and gills of prawn
D. Wings of bat and wings of butterfly

Answer

To determine which of the following is a pair of homologous organs, we first need to understand the definition of homologous organs. Homologous organs are those that have the same origin (or developmental structure) but may serve different functions in different organisms.

Let's analyze the options provided:

1. **Pectoral fin of the fish and the forelimbs of the horse**:
- Both have the same basic structure (origin) as they are derived from the same embryonic tissue.
- They serve different functions: the pectoral fin is used for swimming, while the forelimbs of the horse are used for running.
- Therefore, this pair is homologous.

2. **Wings of the grasshopper and the wings of the crow**:
- Although both are used for flying, they do not share the same origin. The wings of the grasshopper are formed from different structures than those of the crow.
- This makes them analogous organs, not homologous.

3. **Lungs of the rabbit and the gills of the prawn**:
- Both serve the function of respiration, but they do not share the same origin.
- Hence, they are also analogous organs.

4. **Wings of the rat and the wings of the butterfly**:
- Similar to the previous example, while both serve the function of flying, they do not share the same origin.
- Thus, they are analogous organs.

Based on this analysis, the only pair of homologous organs is the **pectoral fin of the fish and the forelimbs of the horse**.

**Final Answer**: The correct answer is the first option: **Pectoral fin of the fish and the forelimbs of the horse**.