Which of the following mineral is required for effective working of the muscular system of the humans ?

Options

A. Na
B. K
C. Ca
D. Cl

Explanation

To determine which mineral is required for the effective working of the muscular system in humans, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Muscle Contraction**:
- The muscular system allows movement through muscle contraction. This involves the sliding of two types of protein filaments: actin and myosin.

2. **Role of Proteins in Muscle Contraction**:
- During contraction, actin and myosin slide over each other. For this process to occur effectively, certain proteins and minerals are necessary.

3. **Identifying Key Proteins**:
- A special protein complex called tropomyosin plays a crucial role in muscle contraction. Tropomyosin binds to calcium ions, which is essential for muscle function.

4. **Calcium's Function**:
- When calcium is present, it binds to tropomyosin, causing a conformational change that uncovers the binding sites on actin. This allows myosin to bind to actin, facilitating muscle contraction.

5. **Evaluating the Options**:
- The question provides four options: sodium, potassium, calcium, and chlorine. Among these, calcium is specifically mentioned as necessary for uncovering the binding sites on actin.

6. **Conclusion**:
- Based on the understanding of muscle contraction and the role of calcium, we conclude that calcium is the mineral required for the effective working of the muscular system in humans.

### Final Answer:
**Calcium is the mineral required for the effective working of the muscular system in humans.**

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