A sphere is a polyhedron.

Answer

**Step-by-Step Solution:**

1. **Understand the Definitions:**
- A **sphere** is defined as a three-dimensional object where all points on its surface are equidistant from a central point. It can be visualized as the surface of a ball.
- A **polyhedron** is a three-dimensional solid that is made up of flat polygonal faces, straight edges, and vertices. The term "polyhedron" comes from the Greek words "poly," meaning many, and "hedron," meaning faces.

2. **Analyze the Characteristics of a Sphere:**
- A sphere does not have flat faces; instead, it has a smooth curved surface.
- It has no edges or vertices, which are essential characteristics of polyhedra.

3. **Analyze the Characteristics of a Polyhedron:**
- A polyhedron must consist of multiple flat polygonal faces.
- Each face must meet at edges, and there must be vertices where the edges meet.

4. **Conclusion:**
- Since a sphere does not have the characteristics of a polyhedron (no flat faces, edges, or vertices), we can conclude that a sphere is not a polyhedron.

5. **Final Answer:**
- Therefore, the statement "A sphere is a polyhedron" is **false**.

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