How can density be used to describe Earth’s Layers?

Earth has layers because of density. Dense materials such as iron sank to the middle of the Earth, the center of its gravity. Less dense materials stayed at the top.

i think its c if i'm wrong

radial fractures in a piece of glass look most like which of the following?

a. spokes of a wheel

b. a circle

c. a zig zag

d. none of the above

the correct answer is a. spokes of a wheel

hope this (: