Which of the following is not found in birds

Options

A. Hind limb
B. Pectoral girdle
C. Pelvic girdle
D. Fore limb

Explanation

To answer the question "Which of the following is not found in birds?", we will analyze the options provided and determine which structure is absent in birds.

### Step-by-Step Solution:

1. **Understanding Bird Anatomy**: Birds belong to the class Aves and have specific anatomical adaptations that allow them to fly. This includes modifications in their limbs and skeletal structure.

2. **Evaluating the Options**:
- **Hindlimb**: Birds possess hindlimbs, which are used for perching and grasping branches. Therefore, hindlimbs are present in birds.
- **Pectoral Girdle**: The pectoral girdle, which is typically present in many vertebrates, is not found in birds in its traditional form. Instead, birds have a structure called the furcula (wishbone) that serves a similar purpose for muscle attachment related to flight.
- **Pelvic Girdle**: Birds do have a pelvic girdle, which supports their hindlimbs.
- **Forelimbs**: While forelimbs are present, they are modified into wings for flight, which is a significant adaptation for birds.

3. **Identifying the Correct Answer**: Based on the evaluation, the pectoral girdle is the structure that is not found in birds in its typical form. Instead, birds have adaptations such as the furcula for flight.

4. **Conclusion**: The correct answer to the question is that the pectoral girdle is not found in birds.

### Final Answer:
The structure that is not found in birds is the **pectoral girdle**.