Why does an author use a subplot in a novel?

to resolve the problem that the main characters face

to introduce the conflict that drives the central plot

to prepare readers for sequels to the original text

to develop secondary characters and story lines

to develop secondary characters and story lines

Explanation:

A good story doesn't only focus on one aspect of it. The main character shouldn't be the only character that the reader is aware of, and the main plot shouldn't be the only focus of the story. It's boring that way. Having a subplot helps the author keep the reader entertained and sometimes even on their toes. I hope this helps you!

in this alternate universe, renaissance romeo is now seventeen, an apprentice to a glass maker in venice. modern romeo is planning to go to college. what major do you think he’ll elect?