Final answer:
The ball has the maximum value of acceleration throughout its entire flight because the only acceleration acting on it is the constant acceleration due to gravity.
Step-by-step explanation:
When you throw a ball straight up into the air, the point at which it has the maximum value of acceleration is throughout its entire flight. This is because the only acceleration acting on the ball is due to gravity, which is constant and does not change with the ball's position or velocity. Whether the ball is moving up, at its highest point, or coming back down, the acceleration due to gravity remains at approximately 9.81 m/s2 downward (on the surface of the Earth).