There is proof of it. Such as fossils, records, videos, etc. Dinosaurs and Thylacines for example. Both of these have been extinct for quite some time. Although there is footage of some Thylacines there isn't any of any Dinosaurs. However, there is fossils and bones found from Dinosaurs. There has been fossils from many extinct animals dating back millions of years, therefore proving its a common event through history.
Answer:
The respiratory system includes the nose, mouth, throat, voice box, windpipe, and lungs.
Air enters the respiratory system through the nose or the mouth. If it goes in the nostrils (also called nares), the air is warmed and humidified. Tiny hairs called cilia (SIL-ee-uh) protect the nasal passageways and other parts of the respiratory tract, filtering out dust and other particles that enter the nose through the breathed air.
"You should practice cross training by participating in a wide variety of sports or actives"
