Answer:
Results in global warming
The answer is B) Inca. Extensive road network across plains, deserts and mountains reaching all corners of the empire was one of the notable features of the Inca empire like terraced farming, canals, crop rotation and irrigation as agricultural innovations. It allowed smooth military operations, trading, and the use of runners or chasquis.
Physical factors that affect population density include water supply, climate, relief (shape of the land), vegetation, soils and availability of natural resources and energy. Human factors that affect population density include social, political and economic factors.
Answer:
C. The greater an element's density, the smaller the amount of it found in the crust
Explanation:
The layering of the Earth happened because of the different densities of the elements from which it was made. The denser elements started to sink deeper, the elements with medium density occupied the central part, and the elements with the smallest density remained at the surface. This resulted in the formation of the three basic layers of the Earth, core, mantle and crust. The core is composed of the densest elements, the mantle of the ones with medium density, and the crust from the ones with smallest density.