Which is a compound sentence?

 - Many members of the cat family can purr, but only tigers, lions, jaguars, and leopards can roar.
 - In June, Tori and Emmet will graduate with honors from Dover High School.
The second sentence is the compound sentence. It is made up of two independent clauses joined by the coordinating conjunction but.
Many members of the cat family can purr, but only tigers, lions, jaguars, and leopards can roar.