The evidence from studies of twins and biological and adoptive siblings indicates that genetic influences explain approximately percent of individual variations in personality traits.

50%

Explanation: These studies together show that about half (50%) of the variance in aggressive behavior is explained by genetic influences in both males and females, with the remaining 50% of the variance being explained by environmental factors not shared by family members. Form of aggression (reactive, proactive, direct/physical, indirect/relational), method of assessment (laboratory observation, self-report, ratings by parents and teachers), and age of the subjects—all seem to be significant moderators of the magnitude of genetic and environmental influences on aggressive behavior.

true because they can bargain

answer; presidential election years;