Final answer:
The underlined stage direction in the excerpt from Trifles creates a tense mood by reminding the characters and the reader of where Mrs. Wright calmly sat as she discussed her dead husband.
Step-by-step explanation:
The underlined stage direction in the excerpt from part one of Trifles affects the mood of the scene by creating a tense mood. This is because the emphasis on the rocker reminds the characters and the reader of where Mrs. Wright calmly sat as she discussed her dead husband. The juxtaposition between the quietness of the scene and the potential significance of the rocker adds suspense and unease to the atmosphere.
Learn more about the effect of stage direction on the mood of a scene