In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.

[Q]: Question: The mass of atoms is based on the number of protons and neutrons in what? Answer: nucleus
[A]: The mass of atoms is based on the number of protons and neutrons in nucleus.

[Q]: Question: Which statement best describes the Law of Superposition? Answer: In undisturbed layers of sedimentary rock, the lowest layers contain the older rocks.
[A]: The law of superposition is best described by: in undisturbed layers of sedimentary rock, the lowest layers contain the older rocks.

[Q]: Question: Why is the life cycle of plants so complex? Answer: alternation of generation
[A]:
The life cycle of plants is so complex because of the alternation of generation.