The side characters in novels tend to
a, be less developed than in short stories.
b. have lives and stories of their own
c, be present in every single scene
d. only appear in a few episodes

The side characters in novels tend to:

B. Have lives and stories of their own.

Side characters tend to appear often in the story and are relevant to the protagonist's life.  Although presented as less developed first, throughout the course of the story, side characters can become as significant and complex as the protagonist. Nonetheless, their stories, either complex or not, are often related to the main character.

yes yes it does !

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