Given a scientific question, generate a correct answer to it.

[EX Q]: What "kind" of water may take longer to become contaminated than surface water, while the natural cleaning process may take longer?
[EX A]: groundwater

[EX Q]: What happens if a molecule forms strong bonds to the catalyst?
[EX A]: catalyst gets poisoned

[EX Q]: What are formed by atoms gaining electrons?
[EX A]:
anions