The human body is densely populated with various microorganisms. Statistically speaking, each of the dozens of human cells, from which our body is composed, also comes up with a microbial cell. So although we carry the same number of microbial cells such as our own body cells, these microbes only make up a fraction of our weight because they are much smaller. A person with a body weight of 70 kilograms still carries about 0.2 kilograms, i.e. 200 grams of microorganisms.
