Final answer:
The necessary and proper clause, also known as the elastic clause, gives Congress the power to pass laws that are necessary and proper for carrying out its duties. This clause allows for a loose interpretation of the Constitution and supports Congress's implied powers. It is found in Article I, Section 8 of the Constitution.
Step-by-step explanation:
The section of the Constitution that is used to justify a loose interpretation of the Constitution and give Congress the power to make laws that are necessary and proper for carrying out its duties is called the 'necessary and proper clause' or the 'elastic clause.' This clause is found in Article I, Section 8 of the Constitution. It allows Congress to pass laws that are not specifically mentioned in the Constitution, as long as they are related to one of Congress's enumerated powers.