Change.
Acceleration means going faster
We can calculate the density of the balloon as follows:

Therefore, the balloon will fall
Since the density of air is about 0.00123 g/cm^3 , the balloon is much more dense than the surrounding air. As a result, the balloon weighs more than the air that it displaces so the balloon will fall.
Gregor Mendel was the first person to trace the characteristics of successive generations of a living thing.
Zero.
Acceleration is defined as the change in velocity over time.
Since in your case there is no change, there is no acceleration, so it is zero:
Or in formula: <span>a=<span><span>Δv</span>t</span></span>
Where a=acceleration, <span>Δv</span>=change in velocity and t=time