How does bacteria affect humans?
Bacteria affect humans in both positive and negative ways.
Bacteria are living organism that exist all around and inside of humans. There are bacteria always living in the digestive system of humans. E Coli is a common bacteria that is necessary for the production of some necessary vitamins in the human body. There is a natural flora of bacteria in the human body that is healthy.
Some E coli however can become toxic to the human body causing illness and even death. Other bacteria like streptococci are responsible for strep throat a serious disease.
Without bacteria life on earth would be impossible. Life depends on nitrogen fixing bacteria to bring nitrogen out of the atmosphere for use in living things.
However many bacteria when out of balance cause death and illnesses in humans.
So bacteria affect humans for both good and bad.