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

Input: Consider Input: Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only contract.

Output: Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only do what?


Input: Consider Input: Lead sulfate is the white solid that forms on corroded battery terminals.

Output: What is the white solid that forms on corroded battery terminals?


Input: Consider Input: Living organisms are affected by changes in ph acidic can include basic conditions and what other kinds of conditions.


Output: Living organisms are affected by changes in ph which can include basic conditions and what other kinds of conditions?