What are the outward conical projections on some of the fetal cranial bones?

Answer;

-Ossification (growth) centers

Explanation;

-Ossification is the process of bone formation by osteoblasts. Ossification is distinct from the process of calcification; whereas calcification takes place during the ossification of bones, it can also occur in other tissues.

-Primary ossification center is the first area of a bone to start ossifying. It usually appears during prenatal development in the central part of each developing bone. The secondary ossification centers appear, during the first years of postnatal life, in the epiphyses of the bone (at the ends of the bone).

all these collisions do one thing, and that thing is explained in the last option. when dusst, rocks and ice collide, they harden and form giant layers of rocks or hard ice.

d)   to harden materials to form different parts of earth’s layers

hope it ,

bioteacher101