Final answer:
The elastic clause, or necessary and proper clause, refers to the last enumerated power of Congress allowing it to pass laws deemed 'necessary and proper' for executing its duties, thus enabling Congress to extend its powers beyond the explicit list in the Constitution.
Step-by-step explanation:
The final enumerated power of Congress is often referred to as the elastic clause because it provides a mechanism for Congress to stretch its powers to address unforeseen or additional needs that may arise in governance. Specifically, the elastic clause, found in Article I, Section 8 of the U.S. Constitution, is officially known as the necessary and proper clause.
This clause gives Congress the authority to pass laws deemed "necessary and proper" for executing its enumerated powers. Throughout history, it has enabled Congress to establish regulations and create institutions such as the Internal Revenue Service (IRS) and enforce occupational safety laws, which are not explicitly stated within the Constitution but are considered necessary to perform the duties of governing a modern nation. Thus, the term elastic aptly describes the flexibility this clause provides in legislative actions and the expansion of Congressional powers.