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: In the lungs, oxygen diffuses out of the alveoli and into capillaries.
Example Output: In the lungs, oxygen diffuses out of the alveoli and into where?

Example Input: The stomach mucosa’s epithelial lining consists only of surface mucus cells, which secrete a protective coat of alkaline mucus.
Example Output:
The stomach mucosa’s epithelial lining consists only of surface mucus cells, which secrete a protective coat of what?