An ecosystem can be viewed as the interaction of _ and biologic

If you mean biotic, then its probably abiotic and biotic factors. It is the interaction between organisms and their environment. 

Allusion and illusion. an allusion is an indirect reference, whereas an illusion is something that is unreal or incorrect. each of the nouns has a related verb form: allude “to refer indirectly to,” and illude (not a very common word), which may mean “to delude or deceive” or “to subject to an illusion.”