When the allies began bombing the japanese mainland, casualties were high because the bombings used atomic weaponry. targeted large military bases. were in highly populated areas. occurred throughout the nation.

Highly populated areas

Option C.

Explanation:

Were in highly populated areas, is the right answer.

During the final phase of the Second World War, the U.S. with the consent of the U.K. dropped two atomic bombs on the two highly populated cities of Japan known as Hiroshima and Nagasaki on 6th and 9th August 1945 respectively. Though the main cause of the disaster was the atomic weapons, the casualties were high due to the very fact that the cities were highly populated. The United States by dropping two atom bombs killed around 129,000 Japanese people.

d) all choices are correct

c) troops march forward in close formation against newer, more accurate weapons