What is the answer to this question

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 methods of dealing with economic crisis that were established during the new deal are still used today? choose all answers that are correct. question 9 options: a providing a job for every american citizen b prohibiting any further immigration c regulating the stock market d paying pensions and benefits for the elderly, children, and the handicapped

What does the delta symbol represents in this equation