Every 6 hours, the video game restocks the player’s coin ban…

Every 6 hours, the video game restocks the player’s coin bank. To see if the bank has been restocked, the player must go into the game app. If the player opens the app sooner than 6 hours, the effort is wasted – the bank has not been restocked and the player cannot play. This is a ______ schedule.

Faris puts a sign on his door. When the sign is flipped to t…

Faris puts a sign on his door. When the sign is flipped to the red side, he will not answer the door if a student knocks. When the sign is flipped to the purple side, he will answer the door if a student knocks. His students do not knock on the door when the sign is red. Faris has used _________ to ensure his students do not knock on his door when he is not available.