Basically the Earth is layered because of gravity. The earth formed in the molten state. The liquid iron which is very dense fell to the center. The rest of the earth is made up of silicate materials with SiO2 being the main component.
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Answer:
b. identifying the minerals within it
I don't know what you mean by "D" climate regions, but the cooler the climate, the more likely permafrost will be found. If the climate is warmer, permafrost won't be found because it will be thawed out.
Pollution and smoking... Hope it helps, have a great day!