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

Ex Input:
Age causes reduction of elasticity in all organs.

Ex Output:
What causes reduction of elasticity in all organs?


Ex Input:
Virtually all aquatic organisms depend directly or indirectly on protists for food.

Ex Output:
Virtually all aquatic organisms depend directly or indirectly on what for food?


Ex Input:
The ability of matter to combine chemically with other substances is known as reactivity.

Ex Output:
The ability of matter to combine chemically with other substances is known as?