Which element tends to have more impact on a novel's theme?

These are the answers for the question:

the effect of plot events on a character's growth or development the sensory details used to describe the novel's settings the flat characters who don't change by the end of the story the background information provided in the story's exposition

And this is the correct answer:

the effect of plot events on a character's growth or development

Explanation:

Most stories, including novels, are character driven: this means that is the characters (often a few, specially the protagonists and the main antagonists) who carry the story forward, and part of that process is the character's growth or development, which is influenced by the events of the plot.

This character growth is often the most important element of the novel's theme.