Question

Part of the body having a single pair of bone is:
A. Pelvic girdle
B. External ear
C. Wrist
D. Lower jaw

Answer 1

Hint: Our skeletal system is divided into parts:- axial skeleton and appendicular skeleton. The axial skeleton system consists of skull, vertebral column, sternum and ribs and the appendicular skeleton consists of bones of the limbs and their girdles.

Complete Step by Step Answer:
There are two types of girdles included in the appendicular skeleton that are:- pelvic and pectoral. The bones of the pectoral and pelvic girdles help in the articulation of the upper and lower limbs respectively with the axial skeleton. The pelvic bone consists of a pair of coxal bone (that is 2 coxal bones) where each coxal bone is formed with the fusion of three bones:- ilium, ischium and pubis. The thigh bone articulates with the pelvic girdle at a cavity called acetabulum.

The external ear is made up of cartilage but the middle ear consists of three bones called ear ossicles and comprises malleus, incus and stapes which helps them in passing the sound from air to the cochlea.
The bones of forelimbs consist of humerus, radius, ulna, carpals (which includes 8 wrist bones), metacarpals (which includes 5 palm bones) and phalanges (which includes 14 digits).
At an early stage of life, the lower jaw had two distinct bones but later on the two bones fused to form one.

Thus, the correct answer is option A:- pelvic girdle

Note: If the pelvic girdle gets damaged, then it becomes very difficult to walk or sit without feeling any pain. The symptoms of a bruised pelvic is sharp pain in hip or groin and swelling and tenderness in the skin at the site of injury.