Answer: The control group is the part where you see what happens when you change a variable you want to study/examine. Basically, you need the control group because you need something to see what happens when you change something.
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Answer:
option C
Explanation:
the correct answer is option C.
All the activity such as Radioactive isotopes, differentiation of Earth’s iron core, gravity-driven compression,and meteoric bombardment will make the earth hotter than what it is at present.
Radioactive isotope whose nuclei are unstable dissipate excess energy.
Differentiation of iron core means formation of into layer which includes iron.
meteorite bombardment will affect the atmosphere of the earth which protect harmful radiation.
All these activity will make earth hotter
The outer layer of the Earth is called <span>crust!</span>
