How do sharks replace their teeth - Sharks never worry about losing teeth—hidden conveyor belts inside their jaws replace them nonstop, cycling through tens of thousands over a lifetime to keep their bite permanently razor-sharp. | The Brain Maze

The girl brushed her teeth with cola, convinced it would turn them bright white. At first, it really felt like a miracle. The buildup vanished, her teeth began to shine, and her smile looked flawless. She repeated this routine every morning and evening, sometimes even during the day—pouring cola onto her toothbrush and brushing over and over. Her friends grew jealous, and at school they kept asking how she had managed to whiten her teeth so dramatically. | Hidden Stories