Which class of lever found in the human body is being used by a boy:
when he holds a load on the palm of his hand.

Explanation

To determine which class of lever is being used by a boy when he holds a load on the palm of his hand, we can analyze the situation step by step.

### Step-by-Step Solution:

1. **Understanding Levers**: A lever is a simple machine that consists of a rigid bar that pivots around a point called the fulcrum. There are three classes of levers based on the positions of the load, effort, and fulcrum.

2. **Identifying the Components**:
- **Fulcrum**: In the case of a boy holding a load in his palm, the fulcrum is located at the wrist joint.
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