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

[Q]: The core of a star collapses during a supernova, forming a neutron star.
[A]: The core of a star collapses during what event, forming a neutron star?


[Q]: Energy do ecosystems absorb on the earth.
[A]: What do ecosystems absorb on the earth?


[Q]: There are six types of leptons.
[A]:
How many types of leptons are there?