expedition = "a journey or voyage undertaken by a group of people with a particular purpose, especially that of exploration, scientific research, or war" - Google
This definition applies to the context in which "expedition" is used in the sentence.
expedition = b.) journey
The Answer is individual v. Nature
The authors in various stories develop characters through other characters dialogue in ways of describing how a character feels towards the main character which express is how the author feels about the character.
Your audience can be anybody, children, adults, or any specific group of people. The audience is your reader.