The number of lumbar vertebrae in the human vertebral column is

In mammals,the largest vertebra is

Which elements are most abundant in the formation of bones?

Match the following:
Bone: Number
$(1)$ Skull: $22$
$(2)$ Vertebrae: $33$
$(3)$ Ribs: $24$
$(4)$ Sternum: $1$
$(5)$ Pectoral girdles: $4$
$(6)$ Arms: $60$
$(7)$ Ear ossicles: $6$
$(8)$ Pelvic girdles: $2$
The correct pairing sequence is:

Fused vertebrae in human are
$I.$ Sacral
$II.$ Coccygeal
$III.$ Thoracic
$IV.$ Cervical
$V.$ Lumbar

The function of the skeleton in vertebrates is/are: