Describe the changes in the velocity of a ball thrown straight up into the air. then describe the changes in the ball's acceleration.

There is a displacement. Just because the ball is thrown up, and not crossways, doesn't mean its location is not moving. Remember, positive displacement is together a displacement in the direction east, right, and up.  The velocity is the distance over time. To compute that, you must look how high the ball moved before falling back down. Acceleration is expected to be constant at 9.80m/s^2. That is the force of gravity. But remember that you are disregarding air friction when you are computing the acceleration.

vapour or gas assuming atmospheriv pressure