Given a statement, generate a question such that the answer is contained in that statement.

[Q]: precipitation is essential for life on earth
[A]: What is essential for life on earth?


[Q]: some rain can changes the hue of litmus paper from blue to red
[A]: What color of litmus paper can be changed by rain?


[Q]: An organism that plays a big role as an aquatic autotrophs is:
[A]:
What is an organism that plays a big role as?