Hello,
The answer is "that it shows the similarities of two objects".
Reason:
A comparison is used to tell the similarities of two things. Comparisons are mainly used to in stories to compare the protagonists, and the antagonists. Also for two options for example: Apples, and Oranges. Comparisons are used in any type of writings.
If you need anymore help feel free to ask me!
Hope this helps!
~Nonportrit