Bacterium

Bacteria play a critical role in maintaining the planet's balance:

Bacteria are generally categorized by their shape and the composition of their cell walls: bacterium

Bacteria are microscopic, single-celled organisms that exist in virtually every environment on Earth, from deep-sea vents to the human digestive tract. They are , meaning they lack a nucleus and membrane-bound organelles. While often associated with disease, the vast majority of bacteria are either harmless or essential to life. 1. Structure and Classification Bacteria play a critical role in maintaining the