The authorial voice is best defined as

The voices or speakers used by authors when they seemingly speak for themselves in a book. The use of this term makes it

clear in critical discussion that the narration or presentation of a story is not necessarily to be identified with the biographical

and historical author. Instead, the authorial voice may be another fiction created by the author. It is often considered poor

form for a modern literary critic to equate the authorial voice with the historical author, but this practice was common in the

nineteenth century. In fact, it is naive to assume that the authorial voice is a "real" representation of the historical author.

"the day we found the sharks' teeth" i would say highlight the element of the plot as it sets its boundaries and centers the adventures of them being on a boat and cleaning spit of sand.

a.) it provides a clue to solve the mystery.