instruction:
Given a scientific passage and an answer, generate a question for the given answer.
question:
Passage: Electronegativity is a qualitative measure of how much an atom attracts electrons in a covalent bond. Answer: electrons
answer:
Electronegativity is a qualitative measure of how much an atom attracts what in a covalent bond?

question:
Passage: Images in a plane mirror are reversed left and right but not reversed top and bottom. Answer: plane mirror
answer:
Images in what type of mirror are reversed left and right but not reversed top and bottom?

question:
Passage: Even if Laura didn't try to stop the skateboard, it would stop sooner or later. That's because there's also friction between the wheels and the pavement. Friction is a force that counters all kinds of motion. It occurs whenever two surfaces come into contact. Answer: friction
answer:
What force occurs whenever two surfaces come into contact?