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

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


[Q]: Yeast fermentation causes holes in bread.
[A]: What causes holes in bread?


[Q]: Star clusters are groups of stars called that are smaller than a galaxy.
[A]:
What are groups of stars called that are smaller than a galaxy?