I am semi-retired and I am taking a self-passed and self-taught Armorers course on S&W Revolvers. I hope to become a part-time light Gunsmith in the future. There are about 60 quiz questions that I have answered but during my study and research I am having some concerns related to some of the following quiz question answers. Either I am not sure of the correct answer or I have received conflicting answers. This is really the last batch of quiz questions. Thanks for your help.

Note #4. What part of the gun does the hand touch and push to rotate the cylinder? I have conflicting answers.
a) The cylinder stop
b) The thumb-piece nut
c) The ratchet pads - ????
d) None of the above - ????

Note #9. In single action, the hammer moves the trigger. True or false - ????. I have conflicting answers on this question too.

Note #13. What prevents the hammer from moving rearward if the cylinder is not closed or locked up all of the way?
a) The stock pin
b) The extractor rod collar
c) The locking bolt
d) The bolt

Note #14. A "five screw" revolver is an early or late model gun?
a) Early model
b) Late model

Note #15. The nose of the trigger causes what part to move?
a) The bolt
b) The bolt plunger
c) The cylinder stop
d) The hammer

Note #16. When the trigger is pulled the hand moves up or down?
a) Up
b) Down