4. A team of geologists wants to study hard, solid rock under the surface of Earth. The team is considering drilling down in the North Atlantic Ocean (1) and in Sierra Leone (2). Where will the team find hard, solid rock?

Question

Responses

a
only under 2, because Earth’s outer layer is made of hard, solid rock under continents but not under the ocean
only under 2, because Earth’s outer layer is made of hard, solid rock under continents but not under the ocean

b
under 1 and 2, because Earth’s entire outer layer is made of hard, solid rock
under 1 and 2, because Earth’s entire outer layer is made of hard, solid rock

c
neither under 1 nor 2, because there is water under both places
neither under 1 nor 2, because there is water under both places

d
neither under 1 nor 2, because there is sand and gravel under both places

Answer 1

The best response would be:

b
under 1 and 2, because Earth’s entire outer layer is made of hard, solid rock

Explanation: While the ocean floor (under the North Atlantic Ocean) consists of sediment and, in some areas, soft sedimentary rocks, there is still hard rock (like basalt) beneath the oceanic crust. Additionally, beneath Sierra Leone (a landmass) there is also hard, solid rock as part of the continental crust. Therefore, hard, solid rock exists under both locations, just at different depths and compositions depending on whether it's continental or oceanic crust.