These single-celled organisms can be pathogenic but some can also be edible known as A. bacteria.
What is bacteria?
It is considered as the small single-celled organisms. It is should be considered anywhere on earth and most important to the ecosystem of the planet.
Here the human body should be full of bacteria also it comprise of the more bacterial cells as compared to the human cells.
hence, the option A is correct.
Learn more about organism here: https://brainly.com/question/21849636
