instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only contract.
answer:
Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only do what?


question:
The love canal tragedy was an infamous example of industrial waste dumping.
answer:
Love canal was an infamous example of what type of pollution?


question:
Sediments in oligotrophic lakes contain large amounts of decomposable organic matter.
answer:

Sediments in oligotrophic lakes contain large amounts of what?