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

The reverse process of moving material into a cell is the process of exocytosis.
The reverse process of moving material into a cell is the process of what?

The ability of matter to combine chemically with other substances is known as reactivity.
The ability of matter to combine chemically with other substances is known as?

Objects in motion that return to the same position after a fixed period of time are said to be in harmonic type of motion.

Objects in motion that return to the same position after a fixed period of time are said to be in what type of motion?