Question

The judicial power shall extend to all cases, in law and equity, arising under this Constitution, the laws of the United States, and treaties made, or which shall be made, under their authority.

—Constitution of the United States
Article III

The purpose of this passage from the Constitution is to

identify the jurisdiction of the federal courts.
distinguish between laws and treaties.
establish a system of inferior courts.
place specific limits on the federal courts

Answer 1

identify the jurisdiction of the federal courts.

The clause defines the scope of cases (those arising under the Constitution, federal laws, and treaties) over which the federal judiciary has authority.