instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
Single-celled organisms and multicellular organisms have this in common: both have a way to get rid of waste materials.
answer:
Which characteristic do single-celled organisms and multicellular organisms have in common?

question:
In machines that increase force, such as ramps and doorknobs and nutcrackers, output is greater is the relation between output and input force.
answer:
In machines that increase force, such as ramps and doorknobs and nutcrackers, what is the relation between output and input force?

question:
The male reproductive system consists of structures that produce sperm and secrete testosterone.
answer:
What does the male reproductive system consist of?