A team of geologists wants to study hard, solid rock under the surface of Earth. The team is considering drilling down in Saudi Arabia (1) or in the Arabian Sea (2). Where will the geologists find hard, solid rock?

Question

Responses

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

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

c
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

d
only under 1, because Earth’s outer layer is made of hard, solid rock under continents but not under the ocean

Answer 1

The correct response is:

d only under 1, because Earth’s outer layer is made of hard, solid rock under continents but not under the ocean.

In general, continents are composed of continental crust, which is largely made of hard, solid rock, whereas oceanic areas like the Arabian Sea are typically underlain by oceanic crust, which may also consist of solid rock but is primarily covered by sediment and water. Thus, drilling in Saudi Arabia (1) is more likely to yield hard, solid rock compared to drilling in the Arabian Sea (2).