johnny often hits his brother even though his brother does not do anything to antagonize him. johnny’s aggression is most likely due to a combination of responses his genetic makeup, the fact that aggression can be evolutionarily adaptive, and a lack of neuroplasticity his genetic makeup, the fact that aggression can be evolutionarily adaptive, and a lack of neuroplasticity developmental delays, the fact that aggression can be evolutionarily adaptive, and a lack of neuroplasticity developmental delays, the fact that aggression can be evolutionarily adaptive, and a lack of neuroplasticity the environment he grew up in, developmental delays, and the fact that aggression can be evolutionarily adaptive the environment he grew up in, developmental delays, and the fact that aggression can be evolutionarily adaptive his genetic makeup, developmental delays, and a lack of neuroplasticity his genetic makeup, developmental delays, and a lack of neuroplasticity his genetic makeup, the environment he grew up in, and the fact that aggression can be evolutionarily adaptive