Final answer:
The narrator compares human faces to the Sun using figurative language to highlight qualities such as brightness, warmth, or cheerfulness that are shared between them.
Step-by-step explanation:
The comparison made between human faces and the Sun at the end of the second sentence of the first paragraph is most likely an instance of figurative language, specifically a simile or a metaphor. This literary device is often used to highlight qualities or attributes that are similar between two different things. In this case, the comparison illuminates characteristics such as brightness, warmth, or cheerfulness that faces may have in common with the Sun, suggesting a positive influence or presence akin to how the Sun brings light and life.
In the given sentence, the narrator compares human faces to the Sun in order to convey the idea that just as the Sun brings light and warmth to the world, smiles on human faces can bring happiness and positivity to others. It is a metaphorical comparison used to emphasize the impact of human expressions on people's lives.