The pins push the part out of the tool and they also leave the small round dots you see on the inside of a molded part.
The hoses are used to move water through the mold base and keep everything at a constant temperature.
On opaque parts this is the half that gets polished.
*Unless your part is clear then the core and cavity will have the same finish.
They are typically clear, it makes it easier to see whats happening during fit tests.