Fill in the blanks for this question please

Are substances released into the environment that in excess amounts cause damage

Which animal group is the largest and contains more species from all the other living groups combined? is it mammals or

What is point source pollution of an aquatic ecosystem? a) pollution of freshwater sources b) pollution from many sources that combine into one c) pollution that occurs over a wide area; water that runs off from fields, parking lots, and other land surfaces d) pollution that can easily be identified with a single discharge source, such as an open pipe which drains into a body of water