But not all living creatures breathe or take in air the same way. Plants have tiny openings on the underside of their leaves and stems. These openings open and close to allow carbon dioxide and oxygen to move in and out. Earthworms breathe through a thin film of water on their skin. The water contains oxygen.
Larger animals have organs for breathing.
For example, fish have gills to extract oxygen dissolved in water. A hibernating woodchuck breathes 12 times per hour. At rest, adult humans breathe between 12 and 20 times each minute. Exposure to a chemical from breathing depends partially on how much chemical you breath in. Suppose a hamster is breathing in a toxic chemical and becomes sick.