Question

on average, the resting membrane potential is -70 mv. what does the sign and magnitude of this value tell you?
there is no electrical potential difference between the inside and the outside surfaces of the plasma membrane.
the inside surface of the plasma membrane is much more positively charged than the outside surface.
the inside surface of the plasma membrane is much more negatively charged than the outside surface.
the outside surface of the plasma membrane is much more negatively charged than the inside surface.

Explanation:

Resting membrane potential is calculated as the potential of the inside of the membrane relative to the outside. A negative value (-70 mV) indicates that the inside surface of the plasma membrane is more negatively charged than the outside surface.

Answer:

The inside surface of the plasma membrane is much more negatively charged than the outside surface.