Given a scientific question, generate a correct answer to it.

Ex Input:
Another measure of the effectiveness of a machine is its what?

Ex Output:
mechanical advantage


Ex Input:
What is contained in the cavity of a long bone's central shaft?

Ex Output:
marrow


Ex Input:
What is given off from plants and taken in by animals?

Ex Output:

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
oxygen


