Why do you think frederick douglass had to learn to red and write in secret?

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.