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a microorganism (=very small living thing) found in wet places that consists of a single cell
microorganisms (=very small living things) that consist of a single cell. Some types of bacteria cause diseases and others cause things to decay.
a living thing, especially a bacterium or fungus that causes something to decay by a slow natural process
a type of bacteria in the intestines in the stomach that can make you very ill if it infects something that you eat or drink
biology a very small water creature with a body shaped like a tube and a number of tentacles (=long thin parts) around its mouth
a very small living thing that you can see only with a microscope. Some microorganisms cause disease.
methicillin-resistant Staphylococcus aureus: a type of bacteria that antibiotics cannot kill and can make people very ill. It is often found in hospitals and is sometimes called a superbug.
microorganisms (=very small living things) that are believed to make you more healthy if you eat them
a unicellular living thing consists of one cell only. Amoebas are unicellular.
biology a simple living thing that is smaller than bacteria and that can enter your body and make you ill. If your body can protect itself against a particular virus, then you are immune to it. A vaccine is a medicine that makes you immune to a particular virus