Question: Flat bones of the face and skull are formed by which of the following? a.) Endochondral ossification, where undifferentiated connective tissue is replaced with bone. b.) Endochondral ossification, where cartilage is replaced with bone. c.) Intramembranous ossification, where undifferentiated connective tissue is replaced with bone. d.) Intramembranous ossification, where cartilage is replaced with bone.