a sphere
In geometry, the only shape that has one surface is a plane.
Cylinder
Cylinder
Both. ANY 2-dimensional shape ... that is, a shape drawn in a plane, or on a piece of paper ... has only one surface.
a sphere
Klein Bottle: http://en.wikipedia.org/wiki/Klein_bottle Its circle
The possible could only be a CONE
A sphere.
A 2D shape is flat and only has a surface area whereas a 3D shape is an object that has surface area and volume.
a sphere
A circle or a sphere.