A ball is thrown up and then falls back until it reaches the ground. During its flight, which of the following best describes its motion?

its acceleration is constant, but not its speed

Explanation:

when ball is thrown up side and then fall back down till it reach to ground

so it describe motion with constant acceleration with respect to height speed is continuously changing when it go up side or down side

because ball move with gravity and against the gravity with air friction

so here correct answer is acceleration is constant, but not its speed