Final answer:
The plasma membrane of a neuron in the resting state is very permeable to K+, but almost impermeable to Na+.
Step-by-step explanation:
The plasma membrane of a neuron in the resting state is very permeable to K+, but is almost impermeable to Na+. The resting membrane potential of a neuron is maintained by the difference in concentrations of ions inside and outside the cell, and the selective permeability of the cell membrane. In particular, the high permeability to K+ ions and low permeability to Na+ ions help create and maintain the negative charge inside the cell.