Answer:
Question 1: over 4.5 billion years all the above
Question 2: all the above
Question 3: The force of gravity pulled more and more material into the center of this swirling disk. Eventually, the pressure in the center was so great that hydrogen atoms began to combine and form helium, releasing a tremendous amount of energy.
Question 4: core is made up of heavy elements, such as iron and nickel, and lighter elements, such as potassium and sodium make up the surface.
Question 5: The process through which distinct layers with characteristic chemical and/or physical properties are formed
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Answer:
Postgraduate university studies.
answer
The author develops the central idea by giving examples. The author builds the suspense by using a series of analogies.
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