Answer
Circle with equation $x^2+y^2=4$ in the $z=-2$ plane
Work Step by Step
Since, we have the equation of cylinder $x^2+y^2=4$ and the plane $z=0$ and the points are the intersection between these equations.
The set of points that satisfies the given two equations will have the equation of a circle shifted two points down lying in the xy plane with origin $O$ as center and a circle of radius $2$.
