The answer is external stimulus
Answer:
To clean groundwater you must:
Explanation:
Eliminate the pollution source: An underground tank must be pumped dry and then dug out from the ground. A factory must be required to stop releasing toxic chemicals. Farms must be more careful about the chemicals they put on their fields.
Monitor the extent of the pollutant: Scientists test water in wells. Sometimes they drill wells to test water. They learn how the groundwater is flowing: how fast and in what direction. They study the contaminants in the groundwater. Then they determine where the contaminant plume is going.
Stem Cells. Hope this helps.
B is the only answer that correctly correlates to the question. Heterotrophs are organism that are not able to produce their own source of food. To acquire food, they depend on the organic molecules produced by producers.
