Which choice is an example of an effect of agricultural techniques on the environment?

A good example would be increased levels of oxygen in a pond due to fertilizer sediments in a lake.  The pond is not part of the farm but sediments from the fertilizer have flowed from a lake to the pond that led to high levels of oxygen which did not come from the environment but from farming.

the answer is       political office  

hope this .

answer; archaeologists;