01. Bacteria
Bacteria are very small unicellular organisms that can cause disease in all living creatures – but that are also essential for life.
Read02. Viruses
Viruses are much smaller than bacteria and cannot reproduce outside living cells.
Read 03. Toxins
Toxins are poisonous substances produced by living cells or organisms.
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04. Parasites
Parasites are organisms that live on or inside another living thing, and they place a great strain on the immune system.
Read 05. Fungi
They are unable to produce their own food and feed off other things, mostly dead organic matter. Some fungi are also parasitic.
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