Question

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.

Answer 1

I pretty sure is D I hope this help you

Answer 2

D)The bioindicator is a scale based on the tolerance value of macro-invertebrates in an environment, used to measure water quality in streams.

Step-by-step explanation:

Biotic index is a scale to assess water quality. It analyses the type of organisms present in a water source and is measured on a scale of 1 to 10. To assign biotic index value to a water site, macro invertebrates are collected from the source and sorted into different groups. The different groups are assigned to different levels of tolerance to pollution. Four groups are made on the basis of tolerance: Pollution intolerant, semi-pollution intolerant, semi pollution tolerant, pollution tolerant.

Macro invertebrates are used for assessment because they are abundant in water bodies, extremely mobile and they carry out complete or some part of their life cycle within the water site.