As far as we know, nearly every creature and animal on earth enjoys sleep just like humans do, but the hours of sleep vary greatly. This means that sleep obviously must serve a key purpose for all living things, right? Well, it turns out science doesn’t really have a concrete answer. What we do have is a number of proposed explanations for why we sleep, but scientists can’t really agree on them. There is the theory that the brain is “recharging” when we sleep, there is a theory that claims we are reinforcing things in our brain that we need in day-to-day activity, and another claims we toss out a bunch of useless information in our brain when we sleep. It seems as if sleep is necessary for us to survive, but we don’t really know why. Urdu translation جہاں تک ہم جانتے ہیں، زمین پر تقریباً ہر جاندار اور جانور انسانوں کی طرح نیند سے لطف اندوز ہوتے ہیں، لیکن نیند کے اوقات بہت مختلف ہوتے ہیں۔ اس کا مطلب یہ ہے کہ نیند کو ظاہر ہے کہ تمام جانداروں کے لیے ایک اہم مقصد ہونا چاہیے، ٹھیک ہے؟...