Bacteria

Bacteria are single-celled microorganisms without a nucleus, reproducing through simple cell division. They inhabit diverse environments, from deep within the Earth's crust to the bodies of animals, including humans. While some bacteria can cause diseases, many are beneficial, contributing to the body's health. Remarkably, the human body contains ten times more bacterial cells than human cells, making up 90% of the body's cellular composition.

What are the two roles that bacteria can play in relation to human health?

What percentage of your body is made up of bacteria?