Which clause of the U. S. Constitution provides that, within its own sphere, federal law is supreme and that state law must, in case of conflict, yield?

Supremacy Clause.

Explanation:

Supremacy Clause has found its place in Article VI, Paragraph 2 of the constitution of the United States of America. This specifies that the central constitution and, generally speaking, federal law take precedence over state laws and even constitutions of states. This forbids states from intervening with the exercise of their constitutional powers by the federal government, and from taking on any duties that are delegated solely to the federal government.

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