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

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

Sexual reproduction, in general, relies on sets of cells that are precursors for eggs and sperm.
What kind of reproduction, in general, relies on sets of cells that are precursors for eggs and sperm?

Echinoderms possess a water-based circulatory system.

What kind of system do echinoderms possess?