Lifting of hand is caused by the contraction of muscles.

Explanation

**Step-by-Step Solution:**

1. **Understanding Muscle Function**: The statement mentions that lifting the hand is caused by the contraction of muscles. Muscles are responsible for movement in our body.

2. **Identifying the Muscles Involved**: In the arm, there are two main muscles that play a crucial role in lifting the hand: the biceps and the triceps.

3. **Role of Biceps and Triceps**:
- **Biceps**: Located at the front of the upper arm, the biceps contract to lift the forearm.
- **Triceps**: Located at the back of the upper arm, the triceps contract to straighten the arm.

4. **Mechanism of Movement**: When you want to lift your hand, the biceps contract while the triceps relax. This contraction of the biceps pulls the forearm upward.

5. **Conclusion**: The statement that lifting the hand is caused by the contraction of muscles is correct. The movement is a result of the coordinated action between the biceps and triceps.

6. **Final Answer**: Therefore, the statement is true.

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