Exam tomorrow? Hit the sack early tonight

over time the one thing that has remained common amongst all animals is sleep. Even the evolutionary forces decided to leave this basic physiological need untouched. The various theories behind what makes sleep tick range from conservation of energy to a time for cell repair. Now experiments on the sleeping mechanism of the fruit fly, Drosophila, make obvious a known but unheeded fact: sleep gives the nervous system time to rejuvenate. A good night