Examine the map, identify what the population density suggests.
A. Population density tends to stay the same over time.
B. People are concentrated near water.
C. The highest concentration of people are near water and along trade routes.
D. The population is migrating inland.

When a lake, river or other aquatic  system  becomes  eutrophic, it can have serious negative effects on other organisms like fish, birds and even people.if an algal bloom is so bad that it causes wide-spread death  in  the  water, the organisms that die will all sink to the bottom and start to decompose.