Point Z is the midpoint of line segment \( XY \). Since \( XY = 22 \) units, the length of \( ZY \) (which is half of \( XY \)) will be:
\[ ZY = \frac{XY}{2} = \frac{22}{2} = 11 \text{ units} \]
Therefore, the correct response is:
Point Z is the midpoint of \( XY \). \( ZY = 11 \) units.