Respuesta :
Answer:
River ecosystems are flowing waters that drain the landscape, and include the biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions of its many parts.
Explanation: it should be both
Answer:
Ecosystems mostly consist of both - abiotic and biotic factors. For that reason the answer which would properly address your question would be A - biotic and abiotic factors. Biotic factors are considered to represent the part of nature that are living and affect other organisms while abiotic factors are things which do not affect other living compounds.