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

The newest, outer layers of secondary xylem are called sapwood.
What are the newest, outer layers of secondary xylem called?

Rainfall weather phenomenon increases the rate of weathering in rock and soil.
What weather phenomenon increases the rate of weathering in rock and soil?

Molecular compounds are inorganic compounds that take the form of discrete molecules called.
What are inorganic compounds that take the form of discrete molecules called?