Three
Yes. You require three non-collinear points to uniquely define a plane!
Yes. In fact any three points that are not collinear define a plane and therefore MUST lie on a plane.
3 non-collinear points define one plane.
A plane
Any Euclidean plane has infinitely many points.
3
3 or more
no
No, 2 points define a line, 3 points define a plane.
1 line cause every plane contains atleast 3 or more noncollinear points
1, exactly 1 plane will