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C) Erosion

D) Iron, Magnesium and Sodium Ions

E) Mountains (If I am wrong please comment.)

Explanation:

C) In the long run, cutting of trees on slopes leads to a gradual decrease in mass stability as a result of the decay of roots which previously acted as tensile reinforcements in the slope. Root decay can also lead to the formation of pipes in a slopes which promote internal or seepage erosion.

D) NASA's Mars Atmosphere and Volatile Evolution (MAVEN) orbiter has spotted iron, magnesium and sodium ions

E) Mountains