Which statement BEST describes an organ? the basic unit of all living things; a building block
the smallest unit in a system that can function on its own
the process in which tissues combine
A group of tissues joined together to perform a specific function

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.