1. Johnny is aggressive. how do i write this sentence in a profesional way

What refers to the existence of more than one level of government in the country

The controlled use of fire by hominids: (a) limited the expansion of hominids into certain environments, such as dry grasslands. (b) decreased the amount of food energy available in the hominid diet. (c) contributed to geographical expansion and food production techniques in positive ways. (d) has been shown to contribute little to the digestive process of hominids.

Which type of learning occurs when you observe how other people act?