Organ (biology)

In biology, an organ is a group of tissues that work together in an organism. They specialise in particular vital functions. They create an organ system which, as a whole, is an organism.

These are examples of organs:
 Heart
 Lungs
 Brain
 Ear
 Eye
 Gall bladder
 Stomach
 Spleen
 Bones
 Pancreas
 Kidneys
 Liver
 Intestine
 Skin
 Uterus
 Bladder

 Classification 
Organelles > Cells > Tissues > Organs > Organ systems > Organism