Final answer:
The crust layer of Earth is rich in humus and it is where soil is formed and where we find most of the Earth's vegetation.
Step-by-step explanation:
The crust layer of Earth is rich in humus. The crust is the outer layer of the Earth's surface. It is relatively thin compared to the other layers and is made up of solid rocks and soil. The crust is where soil is formed and where we find most of the Earth's vegetation.