Short answers, pulled from the story.
Human behavior is the potential and expressed capacity, mentally, physically, and socially, of individuals or groups to respond to internal and external stimuli throughout their lives. It is driven by environmental and genetic factors, and also by thoughts and feelings that reveal a person's attitudes and values.
The nature versus nurture debate is one of the fundamental divisions in the study of human behavior, considering whether conduct is affected predominantly by genetic or environmental factors. Genes do not guarantee behaviors, but inherited traits can make a person more likely to act a certain way, often in conjunction with environmental influences.
Human behavior is studied across the social sciences, including psychology, sociology, Gender Studies, ethology, and their various branches. The study is interdisciplinary, also drawing on anthropology, neuroscience, economics, political science, criminology, public health, and emerging fields such as cyberpsychology and environmental psychology, as well as neurology and evolutionary biology.
Twin studies are a common method because twins with identical genomes can be compared to isolate genetic and environmental factors in behavior. Through twin studies, lifestyle, susceptibility to disease, and unhealthy behaviors have all been identified as having both genetic and environmental indicators.
Human social behavior rests on an advanced theory of mind that lets people attribute thoughts and actions to one another, and through it humans have developed society and culture distinct from other animals. Humans are also unique in using ethical systems to determine behavior and in practicing ethical altruism, while other animals engage only in biological altruism.
Social norms are unwritten expectations that members of a society hold for one another, ingrained in a particular culture and often followed unconsciously. They are enforced by social pressure, and individuals who violate them risk social exclusion; behavior that violates social norms is called deviance.
Modern humans spend an average of 6.5 hours per day engaged in online activities, primarily for information retrieval and social interaction. Digital environments have altered how humans interact and process information, creating new social patterns that differ from traditional face-to-face relationships.