If a body has an acceleration of zero, it means that its velocity is constant. In this case, the speed of the body does not change with time.
Velocity is a vector quantity that includes both magnitude (speed) and direction. When the acceleration is zero, it means that the direction of the body's velocity remains constant, and there is no change in its speed.
So, if a body has an acceleration of zero, its velocity remains constant, and its speed remains the same throughout time.