Ready for a shock? Only about 43% of you is actually YOU! Your cells and DNA, the stuff that makes you human. The other 57% is microscopic creatures that help you function properly. So no worries, these non-human guests are supposed to be there! There are plenty more incredible body facts to go with that! Like that your brain is about the size of a pillow case if you could spread it all out! Talk about big brain time!

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