Which of the following pair is homologous organ?

Options

A. Wings of birds and locust
B. Wings of birds (sparrow) and pectoral fins of fish
C. Wings of bat and butterfly
D. Legs of frog and cockroach

Explanation

To determine which pair of organs is homologous, we need to understand the concept of homologous organs in evolutionary biology. Here’s a step-by-step solution to the question:

### Step-by-Step Solution:

1. **Define Homologous Organs**: Homologous organs are those that have a similar anatomical structure but may serve different functions. They arise from a common ancestor and show divergent evolution.

2. **Identify Examples of Homologous Organs**: Common examples of homologous organs include the forelimbs of vertebrates such as humans, bats, whales, and cheetahs. Despite their different functions (grasping, flying, swimming, running), they share a similar structural framework (humerus, radius, ulna, etc.).

3. **Analyze the Given Options**: The question likely provides several pairs of organs. We need to analyze each pair to determine if they share a common ancestor and have a similar anatomical structure.

4. **Evaluate the Legs of Frog and Cockroach**:
- **Frog’s Legs**: Frogs are amphibians, and their legs are adapted for jumping.
- **Cockroach’s Legs**: Cockroaches are insects, and their legs are adapted for walking.
- Both the frog and cockroach legs have evolved from a common ancestor, making them homologous despite their different functions.

5. **Compare Other Options**:
- **Wings of Birds and Locusts**: These are not homologous as they evolved from different ancestors.
- **Wings of Bats and Butterflies**: These are also not homologous; they serve the same function (flying) but have different structures.
- **Pectoral Fins of Fishes**: These are adapted for swimming and are not homologous to the wings of birds.

6. **Conclusion**: Based on the analysis, the correct answer is that the legs of the frog and the legs of the cockroach are homologous organs.

### Final Answer:
The homologous organ pair is the **legs of the frog and the legs of the cockroach**.

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