Which of the following is a book convention?

A book convention refers to the accepted practices or elements that define what a book is and how it is structured. When considering the correct answer, the spine of a book is a crucial element because it serves multiple purposes: it provides structural integrity, allows for the binding of the pages, and is typically where the title and author’s name are displayed. The spine is essential for the identification and organization of books on shelves, which is a significant aspect of publishing and library science.

In contrast, while having pictures, pages, and being bound are also characteristics of many books, they do not universally apply as conventions. For example, some books, like certain types of manuals or poetry collections, may not have illustrations. Additionally, some formats, such as e-books or digital formats, may not have a physical spine, but they are still considered books in a broader sense. Thus, the spine exemplifies a core convention that is integral to the physical identity of a traditional book.