Answer: (32/3)pi or 32pi/3 cubic units
Explanation
First we use the given surface area to find the radius r.
SA = 4*pi*r^2
16pi = 4pi*r^2
(16pi)/(4pi) = r^2
4 = r^2
r = sqrt(4) ... keep in mind r is positive
r = 2
The radius is 2.
We can now find the volume.
V = (4/3)pi*r^3
V = (4/3)pi*2^3
V = (32/3)pi
This is the same as writing 32pi/3
It's not clear what units you are using. But the most generic volume units would be "cubic units" which we can abbreviate to [tex]\text{units}^3[/tex]
Replace "units" with something like "inches" or "centimeters" if needed.