Bacteria are the simplest true living organism. Unlike other living cells, bacteria do not have a nucleus. Instead, their genes are scattered throughout their interior. Bacteria have a thick protective cell wall. There are thousands of bacteria in every cubic metre of air you breathe, and everything you touch is loaded with bacteria. They even live inside your body.
Although bacteria can cause disease, the majorities of them are completely harmless and carry out the vital function of breaking down dead and waste materials. Bacteria in the gut, for example, help the body’s digestive processes.
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