Which muscles are primarily involved in locomotory actions and changes of body postures:

Options

A. Cardiac muscles
B. Smooth muscles
C. Skeletal muscles
D. All of the above

Answer

To answer the question regarding which muscles are primarily involved in locomotory actions and changes of body postures, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Types of Muscles**: Understand the three main types of muscles in the human body:
- **Cardiac Muscles**: These are involuntary muscles found in the heart.
- **Smooth Muscles**: These are also involuntary muscles found in various organs and structures.
- **Skeletal Muscles**: These are voluntary muscles that are attached to the bones.

2. **Function of Skeletal Muscles**: Recognize that skeletal muscles are responsible for voluntary movements. They contract to produce movement and are essential for locomotion (e.g., walking, running) and maintaining body posture.

3. **Role in Locomotion and Posture**: Skeletal muscles facilitate various actions:
- **Locomotion**: They enable movement by contracting and pulling on bones.
- **Posture**: They help maintain body positions and stability.

4. **Conclusion**: Based on the functions of the different types of muscles, it is clear that skeletal muscles are primarily involved in locomotory actions and changes of body postures.

5. **Final Answer**: Therefore, the correct answer to the question is **Skeletal Muscles**.