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

A pregnant woman should avoid toxic substances while pregnant.
What should a pregnant woman avoid while pregnant?

The core of a star collapses during a supernova, forming a neutron star.
The core of a star collapses during what event, forming a neutron star?

Mammals may either be herbivores, omnivores or herbivores.
Mammals may either be herbivores, omnivores or what else?