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

[Q]: A volcano chain is formed by subduction of oceanic crust beneath a continental or oceanic plate.
[A]: What kind of chain is formed by subduction of oceanic crust beneath a continental or oceanic plate?

[Q]: The mass remains the same does burning matter affect its mass.
[A]: How does burning matter affect its mass?

[Q]: By 8 weeks, all major organs start developing.
[A]:
By how many weeks do all major organs start developing?