People yawn, because its the fastest way to send air up into your brain, so if you were tired and your not thinking well, you would most likely yawn to get your brain working better.
Insects do not yawn. People necessarily do not yawn only when they are tired. Most people, after reading this, will yawn.
They yawn a whole life time
they yawn because when you yawn it passes on to other people . so you yawn then someone's right next to you then i think they inhale then they start to yawn ?
People in the room began to yawn as the lecturer taught his boring lesson. People are often taught that there are times when it can be rude to yawn.
A yawn is normally a response to a change in activity, although if you did not get enough sleep, you could become tired and yawn.
People yawn when they see someone else do it because it triggers something in the brain so you can't help but yawn. Yawning is contagious.
Maybe, depends on how you look when you yawn. I guess.
People don't just yawn because they're sick, first of all, they're brain sends out a message to the body, and then the body reacts as a yawn. You also yawn when you're tired, or need to lie down.
People yawn because the body reacks to oragans and air gets traped
People yawn because they are bore.....right now,their is no approved causal of yawnimg
They probably just woke up. People yawn when they wake up too.
I have seen a lot of people yawn in my life and never once has any of them ever howled at the same time