Final answer:
The legislative branch, which includes Congress, introduces laws. Congress is bicameral, consisting of the House of Representatives and the Senate, and gets its lawmaking authority from Article I of the Constitution.
Step-by-step explanation:
The branch of the government that introduces laws is the legislative branch. As outlined in the Constitution's Article I, the legislative branch, which comprises Congress, is responsible for creating federal legislation. Congress itself is bicameral, meaning it has two chambers: the House of Representatives and the Senate. Ideas for legislation can originate from various sources, including the public, the executive branch, or the legislators themselves.
Congress has the sole authority to create laws, but these can be checked by the executive branch, where the president can veto proposed laws to prevent them from becoming enacted. Additionally, the judicial branch, particularly through the Supreme Court, can exert influence by reviewing the constitutionality of laws through a process known as judicial review.