Answer : 1 Mark
Reasons : 1 Mark each
Sphere, cone and cylinder are not polyhedrons as they are not made of polygons.
Sphere : Sphere has only one curved face, no polygons as faces. So it is not a polyhedron
Cone : Cone has one circular face, but remaining is a curved surface.So it is not a polyhedron
Cylinder : Cylinder has two circular faces, but remaining is a curved surface.So it is not a polyhedron