Why do we yawn
There is an interesting problem, related to our body, health, live. It is Why do we yawn?
There are different theories about it. I would like to talk about it. The main question -Why do people yawn?
Also there is a question: What is a yawn?
And the last one I would like to suggest: What is a yawn for?
Talk (i.e. write) about it, please, please, please! Thanks a lot in advance!