Final answer:
Administrative agencies primarily exercise power through rule making, creating regulations that interpret and enforce laws within their jurisdiction.
Step-by-step explanation:
The chief way that administrative agencies exercise real power is through rule making, which involves deciding how a law will operate in practice. These agencies issue rules or regulations that explain or enforce statutes, under the authority of the executive branch of government. The rulemaking process is complex and often involves creating procedural guidelines and standard operating procedures that lower-level bureaucrats must follow. While other oversight methods exist, such as congressional hearings, budget control, and the Freedom of Information Act (FOIA), the development and enforcement of regulatory guidelines are a primary mechanism through which agencies have a substantial and direct impact on the execution of public policy.