Groundwater can be caused by leaking septic systems, leaking landfills, and agricultural chemicals.

The answer is pollution.

Groundwater is water under the surface of the Earth which is widely used as a source of freshwater. Thanks to its position, it is not as much vulnerable to pollution such as surface water. However, some leaking of landfills, septic systems and agricultural chemicals that can reach it deep down under the surface can cause groundwater pollution.

Groundwater pollution can be caused by leaking septic systems, leaking landfills, and agricultural chemicals
We often do not realize that our daily activities could caused Groundwater pollution. Many studies have founds a worrying amount of chemical substance and Gasoline that trapped within the soil that could be very dangerous for plants and animals

hope this help

The answer would be b. it is a learned trait

Ithink the answer is d.