Answer:
by conveying how difficult it is to climb the stairs
by introducing a gloomy tone through the description of the stairs Explanation:
The author uses the simile "as heavy as rocks" to describe how Cara's legs feel; therefore, "by conveying how difficult it is to climb the stairs" is a correct answer. The sentence also contributes to the first paragraph's meaning "by introducing a gloomy tone through the description of the staircase."
