Examine the following diagram. Place the labeled layers in order from youngest to oldest. Public Domain

A, B, C, D
C, D, B, A
D, A, B, C
C, B, A, D

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