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

Ex Input:
Carried through body happens if cancer cells enter the blood stream.

Ex Output:
What happens if cancer cells enter the blood stream?

Ex Input:
Protists are thought to be the oldest eukaryotes.

Ex Output:
What is thought to be the oldest eukaryotes?

Ex Input:
The vast majority of earthquake occurs along one of three types of plate boundaries.

Ex Output:
The vast majority of what phenomena occurs along one of three types of plate boundaries?