Final answer:
The passage's main theme centers on overcoming personal fears with the strength and support of family, exemplified by Jeannette's struggle with acrophobia and her family's readiness to help her through it.
Step-by-step explanation:
The main theme of the passage is overcoming fears and the support of family in facing personal challenges. Jeannette's acrophobia is a significant obstacle to her enjoyment of the proposed family activity of climbing Mount Whitney. However, the family's understanding and willingness to accommodate Jeannette's fears serve as a poignant statement about the importance of familial support. As they discuss the possibility of climbing the mountain, it's clear that the family values unity and encouragement when overcoming personal obstacles. This theme is further reinforced by their commitment to facing the climb together and supporting Jeannette even if she feels unable to reach the summit, representing the unwavering nature of family support.