For many years, the evaluation of water quality of north carolina streams was defined in chemical terms, ignoring the biological component. more frequently now, the bioindicator is used to evaluate stream quality. what is the biotic index? a)the bioindicator is a scale based on algae levels, used to measure water quality in streams. b)the bioindicator is a scale based on fungus levels, used to measure water quality in streams. c)the bioindicator is a scale based on coliform bacteria levels, used to measure water quality in streams. d)the bioindicator is a scale based on the tolerance value of macro-invertebrates in an environment, used to measure water quality in streams.