Assertion: yawning | /r/CreatedBy | lack of oxygen
Facets:
Source sentences:
text: If yawning is caused by lack of oxygen, wouldn't people that have smoked for a long time be yawning all the time?!
text: The claim that yawning is caused by lack of oxygen has not been substantiated scientifically.
text: The claim that yawning is caused by lack of oxygen has not been substantiated scientifically.  
text: The claim that yawning is caused by lack of oxygen has not been substantiated scientifically.
text: The claim that yawning is caused by lack of oxygen has not been substantiated scientifically.
text: The claim that yawning is caused by lack of oxygen has not been substantiated scientifically.
text: The claim that yawning is caused by lack of oxygen has not been substantiated scientifically.