3 pairs
Three.
21
A cuboid has 3 pairs of parallel faces.
two.
3 pairs
3 pairs
Three.
21
A cuboid has 3 pairs of parallel faces.
Three pairs.
two.
12
A rectangular prism has six faces, and each pair of opposite faces is parallel to each other. Therefore, a rectangular prism has three pairs of parallel faces.
There are 257 topologically different convex octahedra. Many of these will have no parallel faces. It can have four pairs of parallel faces.
The answer will depend on whether you mean parallel edges or parallel faces.
I'm pretty sure it is 12 pairs of parallel lines.