The question about whose mouth is cleaner, a dog's or a human's has been around for many years. Some people say you can let a dog lick you all day and it's perfectly fine. Some will even claim that kissing a person is a worse idea than kissing an animal. Gross!!
So, what's the truth? Well that's the objective behind performing a science fair project about whose mouth is cleaner. Your experiment and the results will allow you to make a decision and present that decision to the judges.