Osteoid-producing osteoblasts must rely on this organelle to produce primary structures leading to the formation of collagen and calcium-binding proteins.
a. peroxisomes
b. ribosomes
c. mitochondria
d. centrioles

The correct answer is option b. "Ribosomes".

Explanation:

Osteoid-producing osteoblast must rely on ribosomes to produce the primary structures leading to the formation of collagen and calcium-binding proteins. Ribosomes are organelles whose main function is to produce proteins, therefore, this organelle is the one that must function in order to osteoid-producing osteoblast could produce the proteins that it needs.

layer 3 is younger than layer 6.

yes, because even though a theory has a  lot of evidence to support it, it is not always true