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.

Example Input: Question: What is at the top of the mesosphere? Answer: mesopause
Example Output: The mesopause is at the top of the mesosphere.

Example Input: Question: What is the highest taxon in the classification of living things? Answer: a domain
Example Output: A domain is the highest taxon in the classification of living things.

Example Input: Question: What distinguishing feature predates the branching of mammals from other vertebrates? Answer: backbone
Example Output:
Backbone distinguishing feature predates the branching of mammals from other vertebrates.