In human beings,the total number of thoracic vertebrae is

The long shaft of a bone is called as:

In humans,out of $X$ pairs of ribs,only $Y$ pairs are true ribs. Select the option that correctly provides the values of $X$ and $Y$ and their explanation.

In man,the thoracic basket is composed of:

Which elements are most abundant in the formation of bones?

Select the correct pair.