hello there
Andrea's point is probably the answer you're looking for, however, you should keep in mind that many (most?) environmental laws are driven more by politics than by the available data. Scientists do research on any number of topics (environmental or not) that have implications for our society. We (scientists) like to think that policy makers take our data and results into consideration when drafting legislation, but I would say that in my experience this rarely happens. For one, there have rarely been any federal legislators who understand science. Even the few physicians who've gone into politics seem largely to fail to understand very basic tenets of science, or at least they don't often demonstrate it with their political actions. Leaving environmental issues, for example, if politicians took science into account, there would be no discussion in any school district in the country about whether or not evolution should be taught in schools, as there are simply *NO* scientists who are qualified to have an opinion who would suggest it shouldn't. Environmental issues are not really any different.
hope that helped bye
The body of water that the city of Los Angeles is located on is called the Los Angeles River. It now flows through a concrete channel on a fixed course, since it has been redrawn after many chaotic floods. The river is rarely used however for fresh water for the city, as it is now very polluted and has urban discharge in it's water, so the aqueducts in the city are now used for the fresh water mainly utilized in Los Angeles.
A. World Population doubles: 20th century
B. Last Drop in Human Population rates: Black Death Pandemic
C. Industrial Revolution: 19th century
D. ??????
Confusing question - reword!
Harm against innocent people