The immature bone found in the fetus and during bone repair is:

A. medullary cavity
This cavity holds marrow (red or yellow), not cartilage.

B. epiphyseal line
The epiphyseal line in adults is a remnant of the epiphyseal plate, but does not contain cartilage.

C. ends of the bones
Both Peter and Paul have articular hyaline cartilage at the ends of long bones for joint function.

D. epiphyseal plate
Only children like Peter have an epiphyseal plate (growth plate), which is made of hyaline cartilage. This area allows for bone lengthening during growth and becomes the epiphyseal line in adults like Paul.

E. in periosteum
The periosteum is a connective tissue membrane around bone-not cartilage.

A. forms the parietal and frontal bones
These bones are formed by intramembranous ossification, not endochondral. Intramembranous ossification occurs directly from mesenchyme.

B. results when the mesenchyme condenses into a fibrous CT around brain
This describes intramembranous ossification, not endochondral. Endochondral ossification uses a cartilage model, not fibrous connective tissue.

C. occurs when bones develop from cartilage models
Endochondral ossification is the process by which long bones and most bones of the body are formed by replacing a hyaline cartilage model with bone.

D. occurs when multiple centers of ossification converge together
While multiple ossification centers do form during endochondral ossification (e.g., primary in diaphysis, secondary in epiphyses), this does not define the process-it’s development from a cartilage model that is essential.