Breathing / Respiration organs are used by most, or all, animals to exchange the gasses necessary for their life functions, known as respiration. These organs come in many forms, some of them apparently having independently evolved:
Anabantoidei Invertebrate trachea Book lung Spiracle Woodlouse Isopoda Respiration (physiology) Mite Gill Scorpion Respiratory system Lung Skin Spider Arthropod