Final answer:
American troops overcame the harsh conditions at Valley Forge through resilience and the aid of Baron von Steuben and improved dramatically as a fighting force. The alliance with France following the Battle of Saratoga provided essential military support.
Therefore, the correct answer is: option "only with the aid they received from nearby Native American groups. and became the core of a determined Continental Army."
Step-by-step explanation:
During the winter of 1777-1778 at Valley Forge, American troops faced a dire situation with harsh conditions, suffering from cold, hunger, and illness. The persistence and resilience of American forces became evident as they endured these hardships and remained determined to continue the fight for independence.
Contrary to notions of defeat or reliance solely on aid from Native Americans or French at this time, the troops were revitalized and transformed into a more professional fighting force under the guidance of Baron von Steuben, a Prussian military officer.
Besides, the alliance with France after the Battle of Saratoga played a pivotal role in bolstering the American cause, providing much-needed military support and turning the tide of the war in favor of the revolutionaries.