Answer: Fibrocartilaginous callus
Step-by-step explanation:
The fractured bone starts healing itself and this helps in joining of the fractured bones. The temporary structure that starts forming is know as fibrocartilage, which is a temporary formation of the fibroblast and the chondroblast which forms when the fractured bones try to heal itself.
This healing process is slow in adults as compared to that of children.This formation can be seen in the X-ray, usually after three week of the fracture.