Deadly diseases is a cause of a decrease in population
Answer:
Igneous rock is formed by the cooling and crystallization of molten magma at volcanoes and mid-ocean ridges, where new crust is generated. Examples of igneous rock are basalt, granite, and andesite (Fig. 7.57 A).
Explanation:
Deserts are a natural barrier between regions, they are difficult to travel through safely due to harsh conditions. Transport of goods and people is more costly and more difficult.
Quaternary- Cenozoic era
Karoo - Paleozoic era
Andean-Saharan - Paleozoic era
Cryogenian - Neoproterozoic era
Huronian - <span>Paleoproterozoic era</span>