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

[EX Q]: Phospholipids are vesicles made of.
[EX A]: What are vesicles made of?

[EX Q]: Phosphate groups are found within phospholipids and nucleotides.
[EX A]: Phosphate groups are found within phospholipids and what else?

[EX Q]: The hottest layers are closest to the core of these best describes the relationship between earth's layers.
[EX A]:
Which of these best describes the relationship between Earth's layers?