Your fingernails grow faster in summer.
744
If Earth's life was compressed into 1 year, then humans would have been around for only 2 seconds.
15
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
One human hair can support 3 ounces.
191
Tigers can see 6 times better at night than humans.
305
A third of the human population sneezes when they look at the Sun. Light can signal the ocular nerve near the sinuses and triggers a sneeze.
18
Early American humans hunted car-size armadillos and used their shells for houses.
12