Final answer:
The Soviet Union suffered the greatest number of casualties in World War II, with an estimated 28 million deaths which included both military and civilian losses. This accounted for around 14% of the country's 1940 population.
Step-by-step explanation:
Greatest Casualties in World War II
The country that suffered the greatest number of casualties in World War II was the Soviet Union. Estimates of Soviet military deaths range from 8.8 to 10.7 million soldiers. Civilian deaths were even higher, with more than thirteen million recorded, and these were the result of military actions, starvation, or disease caused by wartime conditions. In total, the Soviet Union lost about 28 million people to World War II, amounting to approximately 14% of its population at that time.
China also faced devastating losses, with military deaths possibly reaching up to four million and civilian fatalities around sixteen million. In contrast, the United States and the United Kingdom emerged with relatively fewer losses, with 416,000 and 384,000 deaths, respectively. The overall human toll of World War II was astronomical, with an estimated 55 to 60 million deaths, making it the deadliest conflict in human history. Among those were approximately 6 million Jewish victims of the Holocaust.