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

[Q]: When an atom gains or loses an electron it becames a(n) ion.
[A]: When an atom gains or loses an electron it becames an?


[Q]: Muscle groups are controlled by the motor cortex .
[A]: Muscle groups are controlled by what mechanism?


[Q]: Biodiversity is the term for the measurement of the amount of variation of species in a given area.
[A]:
What is the term for the measurement of the amount of variation of species in a given area?