As long as the ball isn't in motion and it is on the green, you can mark its position and wait your turn to play.
Actually yes you can it depends were your ball lands on the green
Yes you can mark a ball anywhere except in a sandtrap
a marker that is flat so a ball can roll over it
No, you may only mark your ball when it is on the green.
yes you can
mark your ball pick it up wipe it put it back pick ball mark up no stroke penalty.
They mark their ball out of courtesy for other players as if one player on the green hits the ball of another they receive a two shot penalty. It is also so the player can clean his ball and line it up.
Not exactly. If his mark would be in your path, he can use any measuring device, (standardly his club length) to make the mark out of your line, and replace it to where it should be before he puts. He has the right to pick up his ball. AlthoughI guess you can always ask!
You take a penalty stroke if you did not let te other player mark their ball.
Once you are on the putting surface i.e the green, you are permitted to mark your ball, clean it and replace it.