why sleep

6 scientific mysteries that, despite being brainstormed in 2018, are still hard to get a satisfactory answer
People have had amazing scientific and technological advances throughout the past century. Science helps somewhat answer the basic question - who are we, what is the world we live
Why do we close our eyes when we sleep - the simple question that scientists also have to scratch their hair
Some people close their eyes when they sleep, others sleep but still open their eyes, eyes closed ... answers will surprise you.