Bacteria’s are unicellular microorganisms. These are among the earliest known life forms on earth. There are different kinds of bacteria, and exists in every conceivable environments all over the world. Few are airborne and others are most prevalent in water, soil, plants, animals, and even people also.
There are many strains of bacteria that are not harmful and some are even helpful, the bacteria found in the human gastrointestinal tract will aid digestion and produce vitamins. There are some who causes infections in humans, which results as bacterial diseases. Some bacteria can be quite hazardous, for example: Salmonella, Pneumonia