Which of the following normally depolarizes a plasma membrane during the action potential?

1. Which of the following normally depolarizes a plasma membrane during the action potential?
a. a decrease in the net flux of K+ ions out of the cell
b. a increase in the net flux of Cl- ions out of the cell
c.a increase in the net flux of Na ions into the cell
d. all of the above
e. none of the above

2. Axoplasmic flow
a. requires actin and calcium
b. can travel in both directions
c. is relatively fast
d. is the movements of proteins
e. is the movements of action potentials

3. Electrical synapses
a. occur when two cells are joined by integrin proteins
b. are characterized by a synaptic cleft
c. occur between two cells of unequal size
d. require the presence of gap junctions
e. none of the above

4. An inhibitory postsynaptic potential in a postsynaptic membrane is produced by the opening of
a. calcium channels
b.channels that  are permeable to both sodium and potassium
c.potassium channels
d.sodium channels
e. calcium and sodium channels