The average ant has about 250,000 brain cells; a human has about 10 billion. It takes 40,000 ants to equal the brain of a human.
Contrary to popular belief, we have more than five senses. We are able to feel heat from a distance, sense where our body parts are and maintain equilibrium when standing, we can sense when we are itchy, tense, and hungry.
Chopping up onions activates a chemical reaction that releases sulfur gas. Water in the human eye reacts with sulfur gas to create sulfuric acid. Although the amount of acid is very small, it's enough to cause a burning sensation in the eye.