<span>Bio-indicators are macro-invertebrates that detect Water Quality based on how tolerant they are to pollution. The number of species of each type of Bio-indicator (pollution tolerant, intolerant, and semi-tolerant) will calculate the index of the water.</span>
<span>All of the populations of different species that occupy and are adapted to a given area are referred as a community.
In a community, there will be many populations of different species. Population is a group of individual in a certain area. The more species in the community, the more complex it is.</span>
D. the 4 types of tissues in the body are: muscle, nerve, connective and epithelial