Was D-Day a simple or
complex operation? How can you
Tell?

Operation Overlord was a complex operation involving the land, sea and air forces of the USA, Britain, Canada and other allies. ... During 1943, however, the Allies achieved a much more favourable strategic position in Europe

It was a complex operation involving the land, sea and air forces of the USA and many other allies. It required extensive planning and preparation, a process dogged by political and strategic arguments.

D-day was a turning point in the war; day of invasion of Normandy which happened June 6, 1944; and over 9,000 soldiers died.

Explanation:

mass production/ assembly line production