Final answer:
The ballad of Mulan is about a heroine who takes her father's place in the army by disguising as a man, fights courageously, and later reveals her true identity, upholding her family's honor.
Step-by-step explanation:
A concise summary of the ballad of Mulan suitable for a 7th-grade English class would focus on the story of Mulan, a heroic figure from ancient Chinese poetry who disguises herself as a man to take her father's place in the army. Bravely fighting for years, she garners great respect for her skills and courage. Upon returning home, she reveals her true identity, shocking her comrades but maintaining her honor and the pride of her family.