Final answer:
The Battle of Trenton was the conflict that raised the Continental army's spirits and encouraged re-enlistment, being a turning point that improved American morale.
Step-by-step explanation:
The battle that boosted the morale of the Continental army and gave soldiers a reason to re-enlist in the war effort was the Battle of Trenton. This victory was crucial because the war had been going poorly for the Americans, and a win provided desperately needed relief and encouragement.
The Continental army, led by George Washington, surprised the Hessians on December 25 and 26, 1776, which led to an important American victory. This battle, along with the subsequent victory at the Battle of Princeton, greatly boosted American morale and helped maintain the sense of colonial unity essential for the success of the revolution.