We do not need to protect ourselves against all bacteria. some live inside our body and are even very important to us,such as the intestinal bacteria. we fall sick only if there are too many bacteria or some harmful bacteria unknown to the body comes from outside, this can happen easily via cuts and bruises on the skin or when our bodies are weak. Antibiotics help against bacterial infections. Unfortunately, they are not always effective because many bacteria have already become resistant' to them. the best way to stay healthy is to strengthen our own immune system. A diet rich in vitamins, i.e., fruits and vegetables and exercise in fresh air helps in keeping us fit.
Bacteria under a microscope: They cause caries.
