Answer:
Correct answer is (a). Assimilation of immigrants into the existing population.
Explanation:
The frequency distribution will not change from generation to generation once a population is in Hardy-Weinberg equilibrium. However, on assimilation of immigrants into the existing population, the equilibrium will definitely change.
Geothermal heat- to provide energy for process like subduction, melting and metamorphism (to drive plate tectonics)
solar energy- for processes like erosion, weathering and transport
Need for raw materials because of the plentiful amount that is in Africa, such as gold, diamonds, wood, and coal.