The metric system is an alternative system of measurement used in most countries, as well as in the United States. The metric system is based on joining one of a series of prefixes, including kilo-, hecto-, deka-, deci-, centi-, and milli-, with a base unit of measurement, such as meter, liter, or gram. (got the answer from google hehe)
Here is one possible answer:
Do allergen-free pillows cause fewer germs to grow
It would become infected with the bacteria and viruses in your body a lot faster, would also absorb other cells due to there being nothing from stopping outside objects from entering its body.
