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

Example Input: Sporopollenin protects the pollen of seed plants and spores of seedless plants.
Example Output: What protects the pollen of seed plants and spores of seedless plants?

Example Input: Urea is made in the liver and excreted in urine.
Example Output: What is made in the liver and excreted in urine?

Example Input: Diffusion is an effective transport mechanism over the spatial scales typically found at cellular level.
Example Output:
Diffusion is an effective transport mechanism over the spatial scales typically found at what level?