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

Some plants have stolons, or stems, that run along the ground and are commonly called runners.
Some plants have stolons, or stems, that run along the ground and are commonly called what?

Protons and neutrons are made of quarks, which are fundamental particles of matter.
A fundamental particle of matter, protons and neutrons are made of these?

A plane mirror has a flat reflective surface and forms only virtual images.

A plane mirror has a flat reflective surface and forms only which kind of images?