What challenges did the french army face in the russian campaign

The challenges the French Army faced was the bitterly cold Russian winter which the French were ill-prepared for. Hitler also made the same mistake.

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.        

stewards ice box was the purchase of alaska from russia and it was called that because people thought it was not a good idea to purchase alaska