Which type of study investigates existing differences to determine possible causes?

The procedure of inserting a new vessel to permanently redirect blood flow to avoid a blockage in an artery:

A) angioplasty. B) arteriotomy. C) bypass graft. D) thrombectomy.

Into which classification of dressings would body and Minerva jackets and walking and spica casts fall?

a. bulky b. one-layer c. pressure d. rigid