In a research paper, the statement that would require a citation is:
- Volcanologists agree that eruptions still cannot be predicted with absolute certainty.
This statement presents a specific claim about the consensus among experts in the field of volcanology. To support this claim and demonstrate credibility, it would be necessary to provide a citation to a reputable source or research study where this agreement among volcanologists is documented. This helps in attributing the information to its original source and allows readers to verify the accuracy and validity of the statement.
The other statements, such as "Washington, DC. is the capital of the United States" and "The landing on the moon is one of the most exciting events in recent history," are generally accepted facts that do not require citation as they are widely known and not subject to debate or interpretation within the academic community.