Which of the following statements is true?
a. endochondral ossification occurs within fibrous connective tissue membranes.
b. endochondral ossification leads to the formation of the clavicles and cranial bones.
c. endochondral ossification converts hyaline cartilage "bone" models into true bones (i. e., hyaline cartilage serves as a template for bone formation).
d. most bones in the body are formed by intramembranous ossification.

c. Endochondral ossification converts hyaline cartilage "bone" models into true bones (i.e., hyaline cartilage serves as a template for bone formation).

Explanation:

Endochondral ossification consists in the progressive replacement of hyaline cartilage with bone tissue, in a process that takes place from the inside out. When development takes place the other way around (that is, from the outside inwards), one speaks of pericondral ossification.

There is another distinct bone development process, which does not involve cartilage and is called intramembrane ossification. There is no calcified tissue in it, and ossification occurs from a membrane, which forms bone