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

[Q]: Stringed instruments can help show the relationship between tension and frequencies in strings.
[A]: Stringed instruments can help show the relationship between tension and what in strings?


[Q]: Bones are made up of different types of tissue.
[A]: Bones are made up of different types of what?


[Q]: Invertebrates (and higher animals) can also be placed in one of two groups based on how they develop as embryos.
[A]:
Invertebrates (and higher animals) can also be placed in one of two groups based on how they develop as what?