The answer is either B or D. Letter A doesn't make sense and letter C isn't right either because you need rainfall to have fertile plains.
Answer:
C. the movement of the Earth's plates
Explanation:
The plates can be thought of like pieces of a cracked shell that rest on the hot, molten rock of Earth's mantle and fit snugly against one another. The heat from radioactive processes within the planet's interior causes the plates to move, sometimes toward and sometimes away from each other.This movement is called plate motion, or tectonic shift. (National ocean service)
The core has the largest density, being made of iron and nickel
The mantle has an intermediate density and the crust has the lowest density.
The answer to this question is the Indus River. Hope that I could help!
