Final answer:
The author is using hyperbole as a figure of speech to exaggerate and create vivid images.
Step-by-step explanation:
The author is using hyperbole as a figure of speech. Hyperbole is an exaggerated statement or claim that is not meant to be taken literally. It is used to emphasize a point or create a vivid image. In this case, the author is using hyperbole to exaggerate the hunger and the number of stars, and to personify opportunity knocking.