This is imagery. The example probably means the girl is doubting herself.
Silicon 14 because the 14 represents the number on periodic table
B. State, in the student’s own words, only the most important ideas
Manuel I just read the book one of them
True - prepositional phrases help your writing flow smoothly and help keep the meaning in your sentences clear.
The purpose of a prepositional phrase is to give more information like an adverb or adjective. They always begin with a preposition (on, around, in front of) and end with a noun.