The correct answer to this open question is the following.
The factors that hindered Germany's invasion of the Soviet Union were the terrible winter conditions with extreme cold, the lack of clothing of the German soldiers, and Hitler's underestimation of the Russian army that defended bravely its territory.
The invasion of the Soviet Union had a code name. It was Operation Barbarossa. The German troops invaded USSR territory on June 22, 1941. Adolph Hitler wanted to invade the western portion of the USSR territory to send Germans to inhabit that area. German troops advanced through the Eastern front and almost captured Moscow but the Russian troops resisted.
