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

Example Input: Ecological pyramids can demonstrate the decrease in energy, biomass or numbers within an ecosystem.
Example Output: What can demonstrate the decrease in energy, biomass or numbers within an ecosystem?

Example Input: Light retains its original color under water because frequency remains the same when light is refracted.
Example Output: Light retains its original color under water because what remains the same when light is refracted?

Example Input: The right atrium receives oxygen-poor blood from the body, then pumps the blood into the right ventricle.
Example Output:
What structure of the heart receives oxygen-poor blood from the body, then pumps the blood into the right ventricle?