1) Our heart beats about 30 million times a year;
2) Our lungs inhale more than 525,000 gallons of air every day;
3) The surface area of the human lung is equal to that of a tennis court;
4) There are 625 sweat glands in one square inch of human skin;
5) Caterpillars have more muscles than humans.
(Published February 13, 2015)
