Which of the following best describes aggression?

Aggression is best described as intentional harm to others because it involves actions taken with the purpose of injuring or causing damage to another individual, whether physically, verbally, or emotionally. This definition captures the essence of aggression, which distinguishes it from other types of behaviors that may be harmful but lack the deliberate intent to inflict harm.

Defensive behavior typically refers to actions taken in response to perceived threats, which do not necessarily have the intention of causing harm to others but rather aim to protect oneself. Passive resistance involves a non-confrontational approach where one may oppose force without direct conflict, while manipulative behavior seeks to control or influence others indirectly rather than through overt aggression. Thus, the clarity of the definition centered around intentionality makes it clear why this description of aggression is the most accurate among the choices given.