Longest bone in lower arm is

Options

A. Ulna
B. Radius
C. Tibia
D. Femur

Answer

**Step-by-Step Solution:**

1. **Identify the Bones in the Lower Arm**: The lower arm consists of two main bones: the ulna and the radius.

2. **Compare the Lengths of the Bones**: Between the ulna and the radius, the ulna is the longer bone.

3. **Eliminate Incorrect Options**:
- The tibia is a bone in the leg, not the lower arm.
- The femur is also a leg bone and is the longest bone in the human body, but it is not part of the lower arm.

4. **Conclude the Correct Answer**: Since the ulna is longer than the radius and is the only bone in the lower arm that fits the criteria, the longest bone in the lower arm is the ulna.

**Final Answer**: The longest bone in the lower arm is the ulna.

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