Which agency is part of the Department of Homeland Security?

The Transportation Security Administration (TSA) is the agency that is part of the Department of Homeland Security (DHS). The TSA was established in response to the events of September 11, 2001, with the primary mission of ensuring the security of the nation's transportation systems, including air travel. This agency implements security measures for airports, manages passenger screening processes, and oversees the security of cargo and other modes of transportation.

In contrast, the Federal Aviation Administration (FAA) is primarily focused on regulating civil aviation and ensuring the safety of flight operations, making it a part of the Department of Transportation. The National Transportation Safety Board (NTSB) serves as an independent federal agency that investigates transportation accidents, including aviation incidents, but is not under the DHS. The Federal Bureau of Investigation (FBI) is part of the Department of Justice and is more focused on federal law enforcement and national security issues rather than transportation security specifically. Therefore, the TSA's role and structure align it directly with the objectives of the DHS, making it the correct answer.