Question

A person(between 11-17) gets up and goes somewhere after sitting 20 mins in a place then he stops at a place for his work but a blackish region surrounds his face for 5secs and he falls on the ground ?after 10secs he feels that now his brain is ok and he gets up but with a heavy brain !What may be the reason behind his feeling of brain as he feels it often???
PLZ ANSWER !!!!!!!!!!!!!!!!
satyajit
you teachers are nothing!!!!!!!!!!!!!!!!!!!!!!

YOU CAN"T GIVE ANY SOLUTION!!!!!!!!!!!!!!!!!!!