Answer:
My biggest fear was that she would sign us up for a 10-mile hike and spend the whole time scoffing at our inferior endurance.
Explanation:
The sentence from Paragraph 2 that best demonstrates the tension during the rising action that indicates that Mariah and Jordyn are not comfortable with each other at first is "My biggest fear was that she would sign us up for a 10-mile hike and spend the whole time scoffing at our inferior endurance".
When one has fear about someone, he/she wouldn't be comfortable with that person. Therefore, having stated that she had the "greatest fear", that means this statement shows/demonstrates the tension of what made them uncomfortable with each other.
