Help what would you do

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.

According to the federal regulations, human subjects are living individuals about whom an investigator conducting research obtains information through interaction or intervention with the individual, and uses, studies, or analyzes the information; or:

In the equation to find gdp (c+g+i+nx) how doe we find net exports? your a. exports + imports b. exports - imports c. exports + imports + balance of payments d. exports - imports + balance of trade