This is a question from the Exit Quiz of the library online orientation, Begin Research. Keywords and database searching are covered in several sections of Begin Research, such as Discovery Tools and Expert Searches.
Here is a hint, though, for identifying good keywords and phrases to use when searching for information about global warming. It is very useful to identify and search for synonyms (phrase that means exactly or nearly the same as another word or phrase). The correct answer choice for this quiz question offers you two keyword phrases that are often used interchangeably with the term, "global warming."
