Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Input: Consider Input: The newest, outer layers of secondary xylem are called sapwood.

Output: What are the newest, outer layers of secondary xylem called?


Input: Consider Input: If an air mass forms over an ocean it is called a maritime air mass.

Output: If an air mass forms over an ocean it is called what type of air mass?


Input: Consider Input: Interstitial carbides are produced by the reaction of most transition metals at high temperatures with carbon element.
Output: Interstitial carbides are produced by the reaction of most transition metals at high temperatures with what element?