Final answer:
The Model Rules of Professional Conduct were established by the American Bar Association and serve as the code of conduct for legal professionals in the U.S.
Step-by-step explanation:
The Model Rules of Professional Conduct for attorneys were established by the American Bar Association (ABA). These rules serve as a code of conduct for legal professionals in the United States. The ABA's Model Rules set out standards for ethical behavior and guide attorneys in their professional duties. Membership in the ABA or a state bar association may be required to practice law, emphasizing the significance of these established rules.