Part of the body having a single pair of bones is
(a) Pelvic girdle
(b) External ear
(c) Wrist
(d) Lower jaw

Options

A. Pelvic girdle
B. External ear
C. Wrist
D. Lower jaw

Answer

To determine which part of the body has a single pair of bones, we can analyze each option provided:

1. **Pelvic Girdle (Option A)**: The pelvic girdle consists of a single pair of bones known as the hip bones. Each hip bone is formed by the fusion of three bones: ilium, ischium, and pubis. The two hip bones are connected at the front by a cartilage called the pubic symphysis and are attached to the sacrum at the back. Therefore, the pelvic girdle indeed has a single pair of bones.

2. **External Ear (Option B)**: The external ear consists of two structures, one on each side of the head. Therefore, it does not represent a single pair of bones.

3. **Wrist (Option C)**: The wrist is made up of multiple bones (eight carpal bones) on each side, resulting in two sets of bones. Thus, it does not qualify as having a single pair of bones.

4. **Lower Jaw (Option D)**: The lower jaw, or mandible, is a single bone but is often considered in terms of its paired relationship with the upper jaw (maxilla). However, it does not consist of two separate bones like the hip bones.

Based on this analysis, the correct answer is:

**(a) Pelvic girdle**