Question

Supporters of using the atomic bomb against Japan at the end of World War II thought an invasion would
cost too many American lives.
not be successful.
be opposed by the American people.
require the navy to build too many ships.

Answer 1

cost too many American lives.

Supporters argued that a full-scale invasion of Japan (Operation Downfall) would result in extremely high U.S. and Allied casualties, so using the atomic bomb was seen as a way to force a quick surrender and avoid that bloodshed.