Which are not homologous?

Options

A. Fore arm of humans and fins of fishes
B. Wings of bat and insects
C. Fins of fishes and flippers of whales
D. Human fore arms, Bat's wings and flippers of whale.

Answer

To determine which of the given options are not homologous, we need to understand the concept of homologous organs. Homologous organs are those that have similar structures and origins but may serve different functions. Let's analyze the options provided:

1. **Forearm of women and fins of fishes**:
- The forearm of women (and humans in general) has a similar bone structure to that of the fins of fishes, indicating a common evolutionary origin. However, they serve different functions (grasping vs. swimming). Therefore, these are homologous.

2. **Wings of bats and insects**:
- The wings of bats are made of bone and are structurally similar to the forelimbs of other mammals, indicating a common origin. In contrast, the wings of insects are made of chitin and do not share a similar structure or origin with bat wings. They serve the same function (flight) but are not homologous.

3. **Fins of fishes and flippers of whales**:
- Both fins of fishes and flippers of whales are adapted for swimming, but they have similar structures and origins (both are derived from the same ancestral limb structure). Therefore, they are homologous.

4. **Human forearm, bat wings, and flippers of whales**:
- All these structures have a similar underlying bone structure, indicating a common evolutionary origin. They serve different functions (manipulation, flight, and swimming, respectively), making them homologous.

Based on this analysis, the option that is not homologous is:

**Wings of bats and insects.**

### Step-by-Step Solution:
1. **Understand the definition of homologous organs**: Similar in structure and origin but different in function.
2. **Analyze the first option**: Forearm of women vs. fins of fishes - they are homologous.
3. **Analyze the second option**: Wings of bats vs. wings of insects - they are not homologous.
4. **Analyze the third option**: Fins of fishes vs. flippers of whales - they are homologous.
5. **Analyze the fourth option**: Human forearm, bat wings, and flippers of whales - they are homologous.
6. **Conclude**: The correct answer is that the wings of bats and insects are not homologous.