16. the answer is...

Senate and House (of Representatives)
(U.S. or national) legislature

Congress makes federal laws. A federal law usually applies to all states and all people in the United States. Either side of Congress -the Senate or the House of Representatives- can propose a bill to address an issue. When the Senate proposes a bill, it sends the bill to a Senate committee. The Senate committee studies the issue and the bill. When the House of Representatives proposes the bill, it sends the bill to the House of Representatives committee. The committee studies the bill and sometimes makes changes to it. Then the bill goes to the full House or Senate for consideration. When each chamber passes its own version of the bill, it often goes to a "conference committee." The conference committee has members from both the House and the Senate. This committee discusses the bill, tries to resolve the differences, and writes a report with the final version of the bill. Then the committee sends the final version of the bill back to both houses for approval. If both houses approve the bill, it is considered "enrolled." An enrolled bill goes to the president to be signed into law. If the president signs the bill, it becomes a federal law.