If you were asked to describe metals and magnetism you could say that
all metals are attracted to magnets because they are able to create their own magnetic field.
all metals are attracted by magnets; this is why we call metals ferromagnetic.
only some metals are attracted to magnets because they do not have a magnetic field.
only some metals are attracted by magnets; these metals are called ferromagnetic.

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.