Human aggression: biological or cultural???

[MissLT]

"Throughout history, humans have been confronted with questions about violence and aggression. Indeed, it sometimes appears as if aggression is an inescapable aspect of life. In today's world of mass media, we are constantly confronted with accounts of violence and aggression, ranging from sports brawls to assaults and murders to revolutions and wars. The seeming universality of aggression has led some people to conclude that humans are "naturally" violent.......... " (Raymond Scupin. Cultural Anthropology. Pg. 206)

Questions:
1. What are the causes of human aggression?
2. Is violence inbred, or is it learned?
3. If cultural norms and values can promote violence, can they also eliminate or sharply reduce it?
4. Can you forsee a society (or a world) in which conflicts and problems are resolved peacefully? Or, will violence always be with us?