Final answer:
The Federal Register Act of 1935 established the U.S. regulatory system's structure, including presidential documents, executive orders, and regulations, but not Congressional bills.
Step-by-step explanation:
The Federal Register Act, enacted in 1935, helped establish the fundamental legal framework of the U.S. regulatory system. Among the contents of the Federal Register are presidential documents, executive orders, and regulations issued by administrative agencies. These documents serve to explain, enforce, or implement legislation under the authority of the Executive branch of government, with Executive orders often directing the implementation of these laws by the branch's administrators. However, the Federal Register does not contain Congressional bills. Bills proposed and passed by Congress are found in the official legislative records, not in the Federal Register, which focuses on documentation from the executive branch and agencies under their purview.