Biological factors that influence human behavior can consist of our drive to be warm, fed, sheltered, have companionship (with some humans having stronger biological drives to reproduce), and be free from harm and oppression. Our very genetic makeup, and the genetic makeup of most sentient beings, causes us to seek these factors. While humans can absolutely participate in self-destructive behaviors that go against these biological factors, these self-harming behaviors are usually a response to not having one of these basic needs met, or in some cases, from chemical brain inbalance(s). Trauma, social isolation, and lack of resources to have basic needs met are the main causes of self-harming behaviors that are in contradiction with these biological factors of human behaviors.
Socially, humans are partially shaped by our environments. This is the "nurture" part of understanding human behaviors, while biological factors can be considered the "nature" aspects of human behaviors. For instance, our society has deep rooted racism, sexism, and homophobia interwoven into many aspects of the dominant American culture. As such, for example, many white people living in America display some degree of racism (whether it be blatant like calling people racial slurs or committing acts of racial hared, or more subtle, yet just as damaging, like being surprised by a black man with dreadlocks who holds a doctorate degree), and generally have to consciously work to unlearn this social conditioning.