Answer:
The steepness of the line represents the rate of erosion in meters per year.
Explanation:
Official answer.
The correct answer is: an interaction between the biosphere and the geosphere.
The geosphere represents all of the rocks, minerals and ground that are found on and in Earth. It includes the ocean floor, all of the rocks on the surface, and all of the sand in the deserts.
Biosphere on the other hand is composed of all the living organisms on Earth (including human).