Where would a new neuron come from

Neurogenesis does not occur everywhere in the brain but is evident in the hippocampus and olfactory bulb and perhaps in the cerebral cortex. New neurons are born not from mature nerve cells but rather develop from neural stem cells that remain in our brains throughout life.

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.

An em wave does not require a medium, while a mechanical wave does.