Inferences about individuals based on the results of group data on the stability of intelligence test scores may be misleading because: reliability of group data may not be high enough for individual interpretation. scores for a single person can still vary widely. the group may not be representative of the population. the individual may not be part of the group.

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.