When an object is thrown upwards, its acceleration doesn't decrease. It remains constant throughout the entire flight.

Here's why:

* Gravity: The only force acting on the object (ignoring air resistance) is gravity. This force pulls the object downwards with a constant acceleration of approximately 9.8 m/s².

* Velocity: The object's *velocity* changes as it goes up. It starts with an upward velocity, slows down as it rises, reaches zero velocity at its peak, and then starts accelerating downwards.

* Acceleration: Acceleration is the rate of change of velocity. Since the force of gravity is constant, the acceleration due to gravity remains constant throughout the object's flight, even though the velocity changes.

In summary: The object's acceleration is constant and equal to the acceleration due to gravity (g).