$1)$ When working in a $3$D world the camera is generally set to look down the $2)$ Projection from $3$D to the screen is based upon proportions given by two similar $3)$ In both $2$D scrollers and $3$D first person perspective games, when the camera moves, calculations are done as if the camera and $4)$ Why do we separate the game loop from the Key Listener? $5)$ What is choreographed AI$?6)$ Explain how a spatial index is utilized in a game to increase efficiency. $7)$ Explain how scrolling works? $8)$ List the tasks that must be performed each iteration of the game loop. $9)$ Describe a simple chasing algorithm. $10)$ Explain page flipping. $11)$ Why do we need to know the ordering of objects by distance when rendering a $3$D scene? $12)$ In question $11,$ it says $"..$ordering of objects by distance..." Distance from what? $13)$ Explain what billboarding is and how it works. $14)$ Explain what parallax scrolling is and how it is implemented. $15)$ List out the sequence of steps followed by the computer each time it renders a $3$D object.