Question

why do you think we yawn when sleepy or drowsy?

Answer 1

it's a reflex action controlled by medulla oblongata of hind brain

Answer 2

we usually yawn when we are sleepy or drowsy.there are many things that different people think of why we yawn but in recent research scientists have found that we yawn because our body needs a self cooling mechanism to regulate itself from the sorounding environment or inside invironment.yawning helps our body to regulate itself.It is also said when we see someone yawn or hear we uaually also yawn because we are in the same environment and the same heating temperauture.