Which of the following departments does not fall under the Department of Homeland Security?

The Federal Bureau of Investigation (FBI) does not fall under the Department of Homeland Security (DHS). Instead, the FBI is a part of the Department of Justice. The DHS was established to consolidate various agencies and functions related to national security, particularly in response to the events of September 11, 2001.

The other agencies mentioned— the Transportation Security Administration (TSA), the Secret Service, and the Federal Emergency Management Agency (FEMA)—are indeed components of the Department of Homeland Security. The TSA is responsible for security in transportation, the Secret Service protects the President and other dignitaries while also investigating financial crimes, and FEMA focuses on disaster response and recovery. This context illustrates the specific roles and jurisdictions of these agencies, further clarifying why the FBI is the correct answer as it operates independently within the Department of Justice, focusing on federal law enforcement and intelligence.