The thumb of humans moves more freely than other fingers due to the presence of

Options

A. A. gliding joint
B. B. hinge joint
C. C. saddle joint
D. D. pivotal joint

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks why the thumb of humans moves more freely than other fingers. We need to identify the type of joint that allows for this greater range of motion.

2. **Reviewing the Options**: The options provided are:
- A) Gliding joint
- B) Hinge joint
- C) Saddle joint
- D) Pivotal joint

3. **Analyzing Gliding Joints**:
- Gliding joints allow for limited movement between two flat surfaces. They are typically found in areas like the wrists and ankles.
- Conclusion: Gliding joints are not responsible for the thumb's greater mobility.

4. **Analyzing Hinge Joints**:
- Hinge joints allow movement in one direction, similar to the opening and closing of a door. They are found in the elbows and knees.
- Conclusion: Hinge joints do not provide the flexibility needed for the thumb's movement.

5. **Analyzing Saddle Joints**:
- Saddle joints allow for a wide range of motion, including back-and-forth and side-to-side movement. They are specifically found in the thumb, shoulder, and inner ear.
- Conclusion: Saddle joints are responsible for the thumb's greater flexibility compared to other fingers.

6. **Analyzing Pivotal Joints**:
- Pivotal joints allow rotation around an axis, as seen in the neck and arm. They do not provide the flexibility needed for thumb movement.
- Conclusion: Pivotal joints are not related to the thumb's mobility.

7. **Final Conclusion**: Based on the analysis, the type of joint that allows the thumb to move more freely than other fingers is the **saddle joint**. Therefore, the correct answer is option C.