Final answer:
The primary source of federal law to regulate business is the Commerce Clause, which allows Congress to regulate trade among the states, while the Tenth Amendment reserves powers not delegated to the federal government to the states.
Step-by-step explanation:
The primary source of federal law used to regulate business is the Commerce Clause. The Commerce Clause gives Congress the power to regulate trade and commerce among the various states, serving as a fundamental mechanism by which federal legislation can address matters that had previously been managed by states.
This includes setting standards for environmental protection, consumer safety, and even minimum wage laws. The Necessary and Proper Clause allows Congress to pass laws that are deemed necessary and proper for executing its powers, and this can relate closely to regulatory powers under the Commerce Clause.
The Tenth Amendment is the source of powers "reserved" to the states. While the Supremacy Clause establishes that federal law is the supreme law of the land, the Tenth Amendment protects the states by ensuring that powers not delegated to the federal government are reserved to the states or to the people.