Piaget's stages of cognitive development in order are formal operational, sensorimotor, concrete operational, preoperational sensorimotor, preoperational, concrete operational, formal operational preoperational, sensorimotor, formal operational, concrete operational concrete operational, sensorimotor, preoperational, formal operational

In his theory of Cognitive development, Jean Piaget proposed that humans progress through four developmental stages: the sensorimotor, preoperational, concrete operational and formal operational period.

fluid balance is an aspect of the homeostasis of organisms in which the amount of water in the organism needs to be controlled, via osmoregulation and behavior, such that the concentrations of electrolytes (salts in solution) in the various body fluids are kept within healthy ranges. the core principle of fluid balance is that the amount of water lost from the body must equal the amount of water taken in.