Your stomach is constantly bathed in hydrochloric acid. How acidic does it actually get? About the same as orange juice A pH of 1 to 2 — close to battery acid Roughly the acidity of black coffee It's actually slightly basic, not acidic None You're born with a certain number of bones, but adults have fewer. About how many bones does a newborn have? Exactly 206, same as an adult Around 100 About 300 More than 500 None Scientists once said bacteria outnumber your own cells 10 to 1. Newer estimates have shrunk that dramatically. What's the current best guess for the ratio of bacterial cells to human cells in your body? About 1.3 to 1 — close to a tie Still 10 to 1 100 to 1 Humans win by 50 to 1 None If you uncoiled an adult's small intestine and stretched it out, roughly how long would it be? About 3 feet About 20 feet About 50 feet About 100 feet None The smallest bone in your entire body is found in the ear. About how big is it? The size of a quarter About an inch long About 3 millimeters — smaller than a grain of rice About half an inch None Stumper. Almost every part of your body is fed by blood vessels — but one part of the eye has none at all. Which part, and how does it get oxygen? The pupil — it absorbs oxygen from light The cornea — it takes oxygen largely from the air The iris — it shares oxygen with the brain The retina — it makes its own oxygen None Time's up
