Bacteria live all around us in colonies and reproduce quickly. bacteria are so small we can see them without a microscope. Bacteria are single celled microorganisms that live in the air and even in our bodies. There are 10,000 known species of bacteria. There are three types of bacteria. Cocci bacteria are round. Bacilli bacteria are straight in shape, and spiral bacteria look like corkscrew pasta.
Some bacteria are very dangerous. The bubonic plague spread throughout Europe and killed millions of people, all caused by bacteria. But not all bacteria are bad in fact you couldn't survive without some bacteria. Probiotics are bacteria that live in your stomach and help you digest food. Good bacteria is also known as beneficial bacteria and can enhance your health. An adult will have 3 pounds of active bacteria in their body at any one time.