What bones fuse together during childhood?

At birth the cranial bones are not fused so that the head can easily traverse the birth canal. The bones of the hands and feet are not fused so that the wrist and ankles can be more flexable when subject to stress. The bones fuse as a person matures. The carpals and tarsals by the age of 17 usually. The skull by age 2.

Correct answer  is flow

In the lava inside crater