Answer:
Bacteria are single-celled organisms that live in different environments, including cold and hot, and they can also live on or inside the human body.
Most types of bacteria are harmless, on the contrary, they help in the process of digesting food, attacking other microbes and fighting cancer cells, and less than 1% of bacteria are bacteria that cause diseases.
As for viruses, they are very small organisms, smaller than bacteria, consisting of DNA and a protein that coat them, and unlike bacteria, a virus does not reproduce without its presence in the cells of living organisms.
