All the following are examples of homologous organs, except

Options

A. Arm of man and flipper of whale
B. Thorn of Bougainvillea and tendril of Cucurbit
C. Eye of an octopus and eye of a mammal
D. Brain of frog and man

Answer

To solve the question regarding homologous organs, we need to follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Homologous Organs**:
- Homologous organs are those that have a similar origin (anatomical structure) but may serve different functions. They arise from a common ancestor.

2. **Analyze the Options**:
- We need to evaluate each option provided to determine if they are homologous or not.

3. **Evaluate Each Option**:
- **Option A**: Arm of man and flipper of whale
- These are homologous organs because they share a common evolutionary origin but serve different functions (man uses arms for manipulation, while whales use flippers for swimming).

- **Option B**: Thorn of bougainvillea and tendrils of cucurbita
- Both structures are modified forms of leaves and share a common origin, making them homologous.

- **Option C**: Eye of an octopus and eye of mammals
- These are not homologous organs. Although they serve the same function (vision), they have different evolutionary origins, which classifies them as analogous organs.

- **Option D**: Brain of dog and man
- These are homologous organs as they share a common ancestry and have similar structures, even though they may perform different functions.

4. **Identify the Correct Answer**:
- The only pair that does not represent homologous organs is the eye of an octopus and the eye of mammals. Therefore, the correct answer to the question is **Option C**.

### Final Answer:
The eye of an octopus and the eye of mammals are not homologous organs; they are analogous organs.

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