Upside and downside can mean a positive and a negative aspect of something, respectively. However, none of the options here present a couple of something negative and something positive: so I think we need to use the local meaning. So our analogy is:
on one extreme of some location (on the upper side): on the other extreme.
Therefore the best other couple is outside and inside: they also show two opposite locations.
Answer: the best option is the last one. By characterizing a character, the author wants to show different characters' traits. Not only physical, but also emotional and how they are developing throught the story.
Explanation:
An urban area is an area that has developed into a concentration of population and commerce, and a center of regional life and trade. AKA a city.
The answer is D, to provide a moral lesson. The bat has the reader and the bird reflect on the circumstances it is in.
