Why is Mengele known as the “Angel of Death”?

Medical experimentation is the correct answer. Mengele was a German Schutzstaffel (SS) officer and physician during World War II. He is mainly remembered for his actions at the Auschwitz concentration camp, where he performed deadly experiments on prisoners, and was a member of the team of doctors who selected victims to be killed in the gas chambers and was one of the doctors who administered the gas. With Red Army troops sweeping through Poland, Mengele was transferred 170 miles from Auschwitz to the Gross-Rosen concentration camp on 17 January 1945, just 10 days before the arrival of the Soviet forces at Auschwitz.

c. troops marched forward in close formation against newer, more accurate weapons