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

Example Input: Slow-twitch or fast-twitch and oxidative or glycolytic describe what type of fibers?
Example Output: skeletal muscle fibers

Example Input: A black solid by itself, this element is incredibly important because of what it makes when it combines with many other elements, including oxygen?
Example Output: carbon

Example Input: The ostrich, kiwi, rhea, cassowary, and moa are examples of what kind of birds?
Example Output:
flightless