Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

A diet rich in calcium and vitamin d may reduce the risk of osteoporosis and related bone fractures.
A diet rich in calcium and what vitamin may reduce the risk of osteoporosis and related bone fractures?

You call materials that have high resistance to electric current electric insulators.
What do you call materials that have high resistance to electric current?

The cells of all protists have a nucleus.
The cells of all protists have a what?