Question 4 ne what are the two sources of energy that power the earth system? explain the processes involved.

The internal heat source  and the external heat source(sun)

Explanation:

The two sources of energy that powers processes on earth are classified into the internal and external heat sources.

These heat sources powers the internal heat engine and the external heat engine.

The internal heat sources causes earthquake, igneous activities, mantle convection e.t.c. Internal heat sources are derieved from:

The external heat sources provides energy for living processes, drives agent of denudation to work, warms the surface of the earth. The ultimate source of energy for external processes is the sun

b.) plain  

hope this

mercury

explanation:

mercury is the least dense because of its size