What would it be like if we didn't have freedom of speech?

Which of the following statements accurately describe the importance of the american concept of government and democracy? (select all that apply.)

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.

True or false? correlations can only be negative.