In "Binding Memories,” a book’s spine serves as an extended metaphor for the speaker’s support for her sister’s marriage. determination to reach her goals. interest in many different subjects. deep enthusiasm for reading.

support for her sister’s marriage.

Explanation:

From the book Binding Memories, women are regarded as important members of society because of their role in childbirth and as custodians of history.

The author used the idea of a book's spine as a metaphor to show that the narrator is in support of her sister's marriage.