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

[EX Q]: Lichens are not a single organism, but rather an example of a mutualism.
[EX A]: Lichens are not a single organism, but rather an example of a what?

[EX Q]: Sodium-potassium pumps help nerve cells establish a voltage across their plasma membranes.
[EX A]: Sodium-potassium pumps help nerve cells establish a voltage across their what?

[EX Q]: Natural selection evolutionary process has adapted protonephridia to different tasks in different environments.
[EX A]:
What evolutionary process has adapted protonephridia to different tasks in different environments?