Geometry

Question Analysis
This question tests the definition of polyhedron and why a sphere doesn’t qualify.
The main focus is on the key structural elements of polyhedra.

Key Concept Explanation
A polyhedron is a 3D figure with flat polygonal faces, edges, and vertices.
A sphere, though 3D, has:
A curved surface (not flat)
No edges or vertices
Therefore, it is not a polyhedron.

Step-by-Step Solution
Option A: False — a sphere is 3D
Option B: False — a sphere does have constant curvature
Option C: Correct — this explains why it’s not a pol...