Energy or caloric and protein needs are lower on a body weight basis in childhood than during the pre-adolescent toddler or preschool years. The protein requirement of an individual is the lowest level of dietary protein intake that will balance the losses of nitrogen from the body in persons maintaining energy balance at modest levels of physical activity.
All vertebrates have a notochord and a pharyngeal slit which is some of the unique features. The more basic features would be that vertebrates form an endoskeleton, skull and backbone.
