Shut the Box - Bookshelf Edition

Which bit of science trivia do you find most fascinating?

• There is only one letter NOT used on the Periodic Table of Elements - the letter J
• Rub an onion on your foot. Because it travels through your blood stream, you will taste it in less than 60 minutes
• Locked in a sealed room, a person would pass away from carbon dioxide poisoning before dying of oxygen deprivation
• Anatomically speaking, all dogs are identical- 321 bones with 42 permanent teeth