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

[Q]: Mercury is the name of the smallest planet in our solar system, which is also nearest to the sun.
[A]: What is the name of the smallest planet in our solar system, which is also nearest to the sun?


[Q]: The metallic bond is responsible for the properties of metals.
[A]: What is responsible for the properties of metals?


[Q]: Developing cars that run on hydrogen gas can help solve our dependence on nonrenewable fossil fuels.
[A]:
Developing cars that run on hydrogen gas can help solve our dependence on what?