What was one reason the battle of barbarossa became a turning point in the war?

the german army suffered massive casualties.
the german army attacked in the middle of winter.
the german army was overconfident after defeating france.
the german army was weakened from fighting two countries at once.

Me! these questions are based on american people in the south essential questions: question 1: for what reasons will one group of people exploit another? focus questions: question 1: what influenced the development of the south more: geography, economy, or slavery? question 2: what were the economic, political and social arguments for and againsts slavery in the first half of the 19th century.