Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
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If you are cold you are more likely to be hungry because you use energy to keep warm.
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The largest cell in the human body is the female egg and the smallest is the male sperm.
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When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The human brain has the capacity to store everything that you experience.
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