Question

the judicial power of the united states
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.

Explanation:

The passage from the Constitution states that the judicial power (of the federal courts) extends to cases arising under the Constitution, US laws, and treaties. This clearly defines what types of cases the federal courts can handle, which is about their jurisdiction. It doesn't focus on distinguishing laws and treaties (only mentions they are part of the cases), doesn't talk about establishing a system of inferior courts (no details on court - building hierarchy here), and isn't placing limits (says it extends to these cases, not restricting).

Answer:

identify the jurisdiction of the federal courts.