* If you're referring to the Earth's internal layers, the answer is the crust.

* The continental crust is thicker and less dense, forming the continents and the highest mountains (like Mount Everest).

* The oceanic crust is thinner and denser, forming the ocean floor, including the deepest trenches (like the Mariana Trench).

* If you're referring to the Earth's atmospheric layers, then the answer is none of them. The atmosphere doesn't directly form mountains or oceans.

Let me know if you have other questions!