Answer:
the center of the earth is called the core
After looking at the photograph given above, one sedimentary rock that probably metamorphosed to form rock on unit 6 is called limestone. You can also use the sedimentary rock called dolostone. Both will be acceptable answers to this question.
Thailand was never a European colony
In terms of individual states, the answer would be New Jersey. Otherwise, the REGION that is most densely populated is the east coast, specifically the Northeastern part of the U.S.
Hope this helps!