How have humans influenced their environment for ages?​

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.

What are the most populous and least areas of russia and why are some areas more heavily populated than others

On this map which states would the tropic of cancer run through