This first normal mode of oscillation mentioned above is called the fundamental mode of oscillation, and the frequency it corresponds to is called the fundamental frequency or first harmonic frequency. In the simulator try to see . What relation do you notice concerning and

Nps pollution is caused by rainfall or snowmelt moving over and through the ground. nonpoint source pollution can include: excess fertilizers, herbicides and insecticides from agricultural lands and residential areas. oil, grease and toxic chemicals from urban runoff and energy production

This is the answer of your question

Ibelieve the answer is d. macula  hope my answer has you : )