The obturator foramen in the pelvic girdle of a mammal is formed by:

State the number of bones in the human forelimb.

Olecranon fossa is present in which of the following bones?

Give differences: Pectoral girdle and Pelvic girdle.

Choose the correct option $:-$
$(a)$ First seven pairs of ribs are called true ribs.
$(b)$ Sternum is a large triangular bone that is situated at the ventral part of the thorax.
$(c)$ Scapula has a slightly elevated ridge called the spine which projects as a flat,expanded process called the acromion.
$(d)$ Below the acromion is a depression called the glenoid cavity which articulates with the head of the humerus.

In the given figure,the fusion of $X, Y$,and $Z$ bones forms: