1) The document discusses factors that influence adolescent development within families, including parenting styles, sibling relationships, divorce, marital conflict, and economic stress. 2) Authoritative parenting, which is demanding but also responsive, tends to be most beneficial for adolescents, though authoritarian parenting may not be as harmful for some ethnic minority families. 3) Siblings influence each other's development but also try to differentiate themselves, and relationships range from conflictual to supportive.