Synovial joint is exemplified by

Options

A. pivot joint
B. hinge joint
C. ball and socket joint
D. all of these

Explanation

To answer the question "Synovial joint is exemplified by," we will follow these steps:

### Step-by-Step Solution:

1. **Understanding Joints**: Begin by recognizing that joints are points of contact between two bones in the skeletal system. They can be classified into different categories based on their structure and movement capabilities.

2. **Categories of Joints**:
- **Fibrous Joints**: These joints are immovable as the bones are fused together by fibrous connective tissue.
- **Cartilaginous Joints**: These allow limited movement as the bones are connected by cartilage.

3. **Definition of Synovial Joints**: Synovial joints are a specific category that allows for a wide range of movements. They have a fluid-filled cavity (synovial cavity) between the articulating bones, which is filled with synovial fluid.

4. **Examples of Synovial Joints**:
- **Pivot Joint**: An example is the joint between the first and second vertebrae (atlas and axis) in the vertebral column.
- **Hinge Joint**: Examples include the knee and elbow joints, which allow movement in one plane.
- **Ball and Socket Joint**: An example is the shoulder joint, where the humerus fits into the pectoral girdle, allowing for multi-directional movement.

5. **Conclusion**: All the mentioned joints (pivot, hinge, ball and socket) are examples of synovial joints. Therefore, the correct answer to the question is that synovial joints are exemplified by these types of joints.

### Final Answer:
Synovial joints are exemplified by pivot joints, hinge joints, and ball and socket joints.

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