Final answer:
Baron von Steuben's training improved the discipline and training of the Continental Army at Valley Forge in 1777-78.
Step-by-step explanation:
The statement that characterizes events at Valley Forge in the winter of 1777-78 is: Through the training of Baron von Steuben, the continental army emerged as a much tougher and better disciplined force.
During the winter at Valley Forge, the American forces faced severe hardships such as lack of supplies, hunger, and disease. However, the arrival of Baron von Steuben, a Prussian soldier, brought significant improvements to the discipline and training of the Continental Army. His training course transformed the army into a force capable of standing up to the professional British soldiers.