Which of the following medical advancements occurred during the 1950s? OOO
The first successful orthopedic surgery.
A vaccine for chicken pox eliminated the disease in the U. S.
Surgeons began replacing worn-out heart valves with artificial ones.
Doctors began treating cancer patients with chemotherapy.

The correct answer is C) Surgeons began replacing worn-out heart valves with artificial ones.

The medical advancement that occurred during the 1950s is "Surgeons began replacing worn-out heart valves with artificial ones."

During the 1950s, medical researchers discovered new methods to help people with heart diseases. Some great examples are the pacemaker, better techniques for open-heart surgery, and the invention of the artificial heart. These technological advancements represented the opportunity for patients to live a longer life or a quality life.

d gerrymandering is the correct answer