You are given a sentence and your task is to generate another sentence that supports the given input.

[Q]: By convention, no subscript is written when a molecule contains only one atom of an element.
[A]: If only one atom of a specific type is present a subscript is not used.


[Q]: A solution contains a mixture of two or more substances which cannot easily be distinguished from one another.
[A]: All solutions contain at least two substances.


[Q]: The principle of superposition states that in an undisturbed stack of sedimentary strata the oldest layer is at the base and the youngest at the top.
[A]:
The law of superposition is best described by: in undisturbed layers of sedimentary rock, the lowest layers contain the older rocks.


