19. The largest known prime number contains 41,024,320 digits. 20. Frogs breathe and drink through their skin. 21. A bullet ...

Even if you think you learned everything that you needed to know way back in biology class, everyone has knowledge gaps. And ...

Laid end to end, an adult's blood vessels could circle Earth's equator four times, with scientists estimating anywhere between 60,000-100,000 miles of blood vessels in the human body. Your heart ...

You might think that the human body has many holes, but that number shrinks when you stop to consider what counts as a hole. When you purchase through links on our site, we may earn an affiliate ...