Aquifers are made up of gravel and sand characterized by holes and channels, like the pores of a sponge. They hold water that has accumulated over thousands of years. The water moves through the pores of the aquifer rock very slowly. Using this information, what can you predict about our ability to clean up aquifers polluted by pesticides, herbicides, and other toxic chemicals

It turns really difficult -and expensive- to clean or revert the situation of a polluted aquifer, if not impossible.

Explanation:

Once an aquifer has been polluted it turns really difficult -and expensive- to clean it or revert the situation. Because groundwater, together with pollutants, moves slowly through the aquifer, contamination may remain undetected for many years. Once pollution is detected, it might be impossible to predict its expansion and extension underground. Besides, aquifers are connected, so a polluted aquifer may easily contaminate another one.

Different techniques can be applied to clean an aquifer; however, these are so expensive that almost nothing can be done to clean it up.

The contamination source, if detected, can be cut off, but the polluted area is hardly recovered.  

the answer is c. according to past decisions, free speech is not unlimited.