instruction:
Given a fact, create a question that can be answered using the fact. Construct the question such that it is unambiguous, has a unique answer and the answer can be given using the fact.
question:
Fact: mammals give birth to live young
answer:
Birds give birth to their babies while still in an egg. Mammals, however, give birth to their babies?


question:
Fact: herbivores only eat plants
answer:
herbivores do what with plants?


question:
Fact: refraction causes something to look different
answer:

A shoe seems gold and green at first, then at second glance looks blue and silver. This could be due to?