Geometry

Question Analysis
This question requires recognizing subtypes of spheres and comparing them.
The main focus is understanding what distinguishes a sphere from a hemisphere.

Key Concept Explanation
A sphere is fully round with no flat surfaces
A hemisphere is exactly half of a sphere and has one curved surface and one flat circular face

Step-by-Step Solution
A: Hemisphere can be solid or hollow — false → eliminate
B: Both have one curved surface; sphere has no flat part — false → eliminate
C: Correct — hemisphere = half of sphere + flat circular ...