biotic factor-

Biotic, meaning of or related to life, are living factors. Plants, animals, fungi, protist and bacteria are all biotic or living factors.
a biotic factor is a living thing thats affects other living things in some way.

for example when there is to much algae in a body of water with other organisms in it there is less oxygen in the water thus making it harder for the other organisms to live.

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another example of biotic factor is a venus flytrap eating a fly