Mechanism of muscle contraction is best explained by____

Answer

**Step-by-Step Solution:**

1. **Understanding Muscle Structure**: Muscle cells, also known as muscle fibers, are elongated and can be spindle-shaped. These cells contain numerous myofibrils, which are the contractile units of muscle.

2. **Components of Muscle Contraction**: The primary proteins involved in muscle contraction are actin and myosin. These proteins interact to facilitate contraction.

3. **Mechanism of Contraction**: The process of muscle contraction involves the sliding of actin and myosin filaments past each other. This interaction leads to the shortening of the muscle fiber.

4. **Theoretical Framework**: The mechanism of muscle contraction is best explained by the **Sliding Filament Theory**, which was proposed by Huxley in 1954. This theory describes how the actin and myosin filaments slide over one another to produce muscle contraction.

5. **Sarcomere as the Functional Unit**: According to the Sliding Filament Theory, the basic unit of contraction in a muscle is the sarcomere, which is defined by the arrangement of actin and myosin filaments.

6. **Conclusion**: Therefore, the mechanism of muscle contraction is best explained by the Sliding Filament Theory.

**Final Answer**: The mechanism of muscle contraction is best explained by **Sliding Filament Theory**.

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