Geologists have located both oil and natural gas underground in the central United States. Oil and natural gas form from the remains of tiny sea organisms. The remains are buried in ocean sediments and slowly change to fossil fuels over millions of years.

Question

Based on this information,
A.
the central United States must have been covered by sea water at some point in the past.
B.
foreign oil and natural gas must have been imported and pumped into the rock layers of the central United States.
C.
there must be a large ocean deep underground in the central United States.
D.
the oil and natural gas in the central United States must have flowed through the ground from the Gulf of Mexico.

Answer 1

The correct answer is:

A. the central United States must have been covered by sea water at some point in the past.

This conclusion is based on the fact that oil and natural gas are formed from the remains of tiny sea organisms, which implies that those organisms lived in a marine environment, indicating that the area was once covered by seawater.