What is the top layer of the Earth's crust that also supports animal life?

The crust is the top layer of the Earth's structure and plays a crucial role in supporting animal life. This layer is composed of solid rock and is where all terrestrial ecosystems are found, including soils, plant life, and the diverse array of organisms that inhabit various environments. The crust provides essential resources such as minerals and nutrients necessary for life.

In contrast, the mantle lies beneath the crust and is primarily composed of semi-solid rock and magma, making it unsuitable for life as we know it. The lithosphere includes both the crust and the uppermost portion of the mantle, so while it is also important, it is not exclusive to the layer that supports animal life. The asthenosphere, located below the lithosphere, is partially molten and allows for tectonic activity, but it too is not a habitat for living organisms. Thus, the crust is specifically recognized as the layer where animal life resides, making it the correct answer.