Although the war began with Nazi Germany's attack on Poland in September 1939, the United States did not enter the war until after the Japanese bombed the American fleet in Pearl Harbor, Hawaii, on December 7, 1941<span>.</span>
I think it would be the third one
I believe your answers is a..
Answer: Iron Weapons
Explanation:
They found iron more in the Qin dynasty than any other.
B) Human knowledge had doubled every century until the 1900s.
“Knowledge Doubling Curve”, theory created by Buckminster Fuller and exposed in his book Critical Path (1982), held that until 1900 human knowledge had doubled approximately every century. And by the end of World War II, the frame time was reduced: knowledge started to double every 25 years. The pace of knowledge growth would continue increasing.
