Then+she+wanted+to+find+out+why+we+yawn.

= = Revelation Rhianna quickly opened her laptop and looked up yawning on the internet. She found out that there were three theories on yawning.

Theory 1 Yawning makes us drawn in oxygen or remove a build up of carbon dioxide.

Theory 2 Yawning might have something to do with ancestors because they wanted to show their teeth to intimidate others.

Theory 3 Boredom or drossiness causes yawning.