Final answer:
The act that showed great courage by the fathers was their behavior in the battle described in the second passage.
Step-by-step explanation:
The act that showed great courage by the fathers was their behavior in the battle described in the second passage. Despite being outnumbered, the fathers, as referred to in the text, fought bravely in the face of danger, while some regular soldiers displayed cowardice. This act demonstrated courage and bravery.