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

[EX Q]: Humans have 23 pairs pairs of chromosomes.
[EX A]: How many pairs of chromosomes do human have ?

[EX Q]: When gas particles heat up, pressure increase.
[EX A]: Does pressure increase or decrease when gas particles heat up?

[EX Q]: Solar and wind are still expensive compared to fossil fuels.
[EX A]:
Solar and wind are still expensive compared to what?