Bacteria are organisms which, along with viruses, are the smallest organisms that exist in our planet, and they are composed of one single cell (Kusinitz & Hoyle, 2014).
Kusinitz, M., & Hoyle, B. (2014). Bacteria. In K. L. Lerner & B. W. Lerner (Eds.), The Gale Encyclopedia of Science (5th ed., Vol. 1, pp. 455-463). Gale. https://link.gale.com/apps/doc/CX3727800251/GVRL?u=lincclin_mcc&sid=bookmark-GVRL&xid=c651cfc4
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