Which statements are true about polygons? Select three options.

All sides and all angles in a polygon are congruent.
The sides of a polygon are segments that intersect exactly two other segments, one at each endpoint.
In a polygon, all segments with a common endpoint are collinear.
If all of the sides of a convex polygon are extended, none of them will contain any points that are inside the polygon.
The extension of at least one side or diagonal in a concave polygon will contain a point that is inside the polygon.