(1) Pole star is always seen in the north.
Because the pole star, which we have in the south, is too faint that it cannot be seen from the naked eye.
or
Because the earths motion is from east to west and not from south to north, around its own axis.
(2) We never see birds urinating.
They don’t have urethra in their body, by which normally mammals urinate.
(3) Pasteurized milk has more nourishment than the ordinary boiled milk.
Because its normally refrigerated, covered and protected. It is heated for a very short time, which not only kills the microbes but also prevents the delicate proteins and vitamins to loose.
(4) Bees die when they sting human beings.
Their stingers are actually ovipositors, tubular structures extending from the abdomen that sometimes contain eggs. When the barbed stinger is left inside the victim, the honeybee mortally tears her abdomen in the process. They leave their stingers in the wound with a tiny venom sac attached. Fortunately, only about one out of a hundred people are allergic to bee stings, but allergic reactions can be very serious.
(5) Cloudy nights are usually warmer than the clear ones.
Clouds will insolate the lower troposphere, causing the temperature to not cool off as much at night. The clouds form an attic over and entraps the air. This prevents to the heat to get lost in the atmosphere, above the clouds. Ultimately, the heat produced in the vicinity is restored.