Science Olympiad Dynamic Planet Practice Test

Which layer of the Earth is known as the crust?

1. The outermost layer that supports life

2. The layer that consists solely of water

3. The inner core at Earth's center

4. The thick layer between the outer layer and the mantle

The correct answer is: The outermost layer that supports life

The crust is indeed identified as the outermost layer of the Earth and is crucial in supporting life. This layer comprises solid rock and soil, encompassing both continental and oceanic crust. The continental crust contains large land masses, while the oceanic crust resides beneath the oceans. This thin layer is fundamental for various geological and ecological processes, and it acts as a habitat for living organisms, making it a critical component of the Earth's system. The depth of the crust varies, but it is much thinner than the layers beneath it, such as the mantle and the core. The other options identify layers that do not correspond to the crust. Specifically, one option incorrectly describes a water layer, which refers to the oceans rather than any geologic layer. Another suggests the inner core, which is a completely different area entirely. The mention of a thick layer between the outer layer and the mantle also misconstrues the structure of the Earth, as the crust is the outermost layer, not a buffer between the outer layer and the mantle. Hence, the description of the crust as the outermost layer that supports life is both accurate and encompasses its role within the Earth's structure.