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

[EX Q]: Water, air, and milk list includes only examples of matter that can take the shape of a container.
[EX A]: Which list includes only examples of matter that can take the shape of a container?

[EX Q]: Some gametophytes develop underground and form mycorrhizal associations with fungi.
[EX A]: Some gametophytes develop underground and form mycorrhizal associations with what?

[EX Q]: The active transport of ions across the membrane causes an electrical gradient to build up across the plasma membrane.
[EX A]:
The active transport of ions across the membrane causes an electrical gradient to build up across the what?