Answer:
The answer is Caused by living life forms.
Explanation:
All in all, biotic variables are the living segments of a biological community and are arranged into three gatherings: makers or autotrophs, purchasers or heterotrophs, and decomposers or detritivores. Precedents of biotic variables incorporate, Grass as producers.The living things in a biological system are called biotic elements. Living things incorporate plants, creatures, microorganisms, organisms and the sky is the limit from there. The non living parts of a biological community are called abiotic factors. In an environment some abiotic factors are daylight, temperature barometrical gases water and soil.