Which one is not a vestigial organ?

Options

A. Wings of kiwi
B. Coccyx in man
C. Pelvic girdle of python
D. Flipper of seal

Answer

To determine which organ is not a vestigial organ, we need to understand what a vestigial organ is. A vestigial organ is one that has lost its original function through the course of evolution and is present in a reduced form.

### Step-by-Step Solution:

1. **Define Vestigial Organs**: Vestigial organs are remnants of structures that were once functional in ancestral species but have lost their usefulness in the current organism. Examples include the human appendix or the wings of flightless birds.

2. **Analyze the Given Options**: We need to evaluate the options provided to identify which one is not vestigial. The options include:
- A) Wings of Kiwi
- B) Coccyx in man
- C) Pelvic girdle of python
- D) Flipper of seal

3. **Evaluate Each Option**:
- **Wings of Kiwi**: Kiwis are flightless birds, and their wings are not functional for flying. Thus, they are vestigial.
- **Coccyx in Man**: The coccyx, or tailbone, is a remnant of a tail that was functional in our primate ancestors. It serves no significant function today, making it vestigial.
- **Pelvic Girdle of Python**: Pythons are snakes that do not have limbs. Their pelvic girdle is a remnant of a structure that was once useful for limb attachment, so it is also vestigial.
- **Flipper of Seal**: The flipper of a seal is functional and is used for swimming. It is not a remnant of a lost structure, but rather a fully functional adaptation.

4. **Conclusion**: Since the flipper of the seal is functional and serves a purpose, it is not a vestigial organ. Therefore, the correct answer is **D) Flipper of seal**.