In this task you are given a sentence. You must judge whether the object of the main clause is singular(like: apple) or plural(like: apartments). Label the instances as "Singular" or "Plural" based on your judgment.
One example: They both let out relieved breaths at the doctor's words.
Solution is here: Plural
Explanation: "relieved breaths" is the object of the sentence which is plural.

Now, solve this: We hike up and down the massive hill that separates my street from the park.
Solution:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Singular