The bird flies up in what?
Options:
- sky
- mountain
- forest
- nest
- roof Hmmm, let me think.

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
Sky is the region of upper air over the earth. Birds fly up in the air.
So, the answer is sky.