Rumalad küsimused

[scryth]

Samas Wikipedia, mida üldjoontes võib sellistes asjades ka usaldada, seda ei kinnita.

"The exact causes of yawning are still undetermined. The claim that yawning is caused by lack of oxygen has not been substantiated scientifically. Some claim that yawning is not caused by lack of oxygen, for the reason that yawning allegedly reduces oxygen intake compared to normal respiration."
http://en.wikipedia.org/wiki/Yawn