
In the English language, the word "who" is almost always used as a pronoun.
It represents a person, similar to the words "I" and "me".
Writing in third person means you have to talk about everyone, not just one character, using they, she, he, all, basically you don't have one point of view, you have the general point of view of everyone
Gatsby is a clear embodiment of the American Dream: he was born poor and rose to achieve a higher wealth and social status. ... Gatsby's love for Daisy led him to achieve extravagant wealth. In the sense of rising up social rank and obtaining financial success, Gatsby achieved the American Dream.