The density of each layer is affected by the of the material and the amount of it is under.

First, density is determined by composition - what each layer is made of. The rocky materials of the crust are less dense than the iron in the core. The atoms and molecules are different in the two types of materials, and that makes their densities different.

Explanation:

since there isn't any suggested answers i will give you the reason and hopefully you can figure it

south africa, or rather all of africa, has not been in the location in which it is nowadays throughout the geological past. after the super-continent pangaea started to break apart, gondwanaland, in which was africa, moved further south, and parts of it came to be very close to the south pole. because the climate in this part of the world is very cold due to the very dispersed sun rays in there, what is now south africa, started to freeze, and the conditions were right for the formation of glaciers. the glaciers existed up until the period when gondwanaland started to break apart and what is now africa started to move towards north, sp it warmed up and the glaciers melted.

's the question?