Answer
$\sqrt5$ units.
Work Step by Step
RECALL:
The distance $d$ between the points $(x_1, y_1)$ and $(x_2, y_2)$ can be found using the distance formula:
$d = \sqrt{(x_1-x_2)^2+(y_1-y_2)^2}$
Use the formula above to obtain:
$d=\sqrt{(-2-0)^2+(1-0)^2}
\\d=\sqrt{(-2)^2+1^2}
\\d=\sqrt{4+1}
\\d=\sqrt{5}$
Thus, the distance between the two given points is $\sqrt5$ units.