Given data:
V = 72w
Dimension = 9 inches long , 8 inches wide and 10 inches high.
Volume = long x wide x hight
Now, by the given question volume is given by
V = 72 w , that means height of the water in container changes.
And volume depend upon the height of the water contained.
Thus, the height of the container is the independent variable.
The answer is , height of the container is independent.