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

Mesoderm type of cell layer do flatworms have.
What type of cell layer do flatworms have?

Producers in an ecosystem generally get their energy from the sun.
Where do producers in an ecosystem generally get their energy from?

Aerobic respiration has the advantage of releasing more energy.
What type of respiration has the advantage of releasing more energy?