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

Ex Input:
Aerobic exercise helps improve the cardiovascular system, while anaerobic exercise causes muscles to get bigger and stronger.

Ex Output:
Aerobic exercise helps improve the cardiovascular system, while what exercise causes muscles to get bigger and stronger?


Ex Input:
Phospholipids are vesicles made of.

Ex Output:
What are vesicles made of?


Ex Input:
The best explanation for how air masses move across the united states is that the prevailing westerlies move air masses from west to east across the united states but may be deflected by the jet stream.

Ex Output:

Which is the best explanation for how air masses move across the United States?