Which of the following sources of pollution would be the most difficult to track and regulate? a. lawn fertilizer runoff b. a waste treatment plant c. a factory d. a nuclear power plant

Aand b antarctica is a north pole.  field lines enter earth near the north pole.the magnetic pole near antarctica is a north pole.compasses point toward a magnetic pole that is a north pole.field lines circle earth from east to west.a compass can lead a hiker to the geographic north pole.

Iwas thinking the wavelength is one half its original value

Answerbiological;