All of the blood in your body travels through your heart once a minute.
More about science ❯
Belly button lint is made of clothing fibers, hair, and dead skin cells
You’re leaving natgeokids.com
to visit another website!
Ask a parent or guardian to check it out first and remember to stay safe online.
You're leaving our kids' pages to visit a page for grown-ups!
Be sure to check if your parent or guardian is okay with this first.