Action potentials ____. (Multiple Choice)

Action potentials ____.
 
  a. move backwards
  b. are examples of negative feedback
  c. are generated and completed in a matter of milliseconds
  d. are only generated regardless of whether or not the threshold potential is reached
  e. are all the same size

Question 2

When potassium ion channels open, which of the following occurs?
 
  a. potassium ions flow into the axon cytoplasm
  b. the axon cytoplasm becomes more negatively charged
  c. sodium ions diffuse into the axon cytoplasm
  d. the threshold potential is reached
  e. more sodium channels open