I think I almost took the bait here but let me recall the question and see what you guys answered for it. The question, if I recall correctly was something like this –
Name something caused by humans that effects the ecosystem in a negative was 
Name the chemical released from this 
What effect does this have on the environment? 
How can humans reduce or stop this harmful effect?
So my answer to the question went something like this. Initially, I wrote it all on human industrialization with smoke stacks releasing CO2 causing global warming. When I was checking it I read that it said CHEMICAL not gas so I crossed it out and rewrote it with pesticides and how we should use natural predators.
Living Environment Regents June 2009
So many people in my class wrote the factories releasing CO2. Will they get points off?
I can’t feel my face- oh that sucks. Ask your teacher about it tomarrow, you migh only get it wrong fo the sulfer dioxide part because you gave a correct answer for somthing negative effecting the enviornment and a correct answer for how to reduce the effects.
If you ask me, here is what I would say to the above comment. No it wasn’t that CBC or whatever you said, I am pretty sure that it is PCBs in pesticides, you know, the stuff that is illegal now I think that weakens the shells of bird eggs?