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.

Input: Consider Input: Question: What does the base of a nucleotide within dna consist of? Answer: nitrogen

Output: The base of a nucleotide within dna consists of nitrogen.

Input: Consider Input: Question: Which of the following structures is not present in animal cells? Answer: cell wall

Output: A cell wall is not present in animal cells.

Input: Consider Input: Question: What are composed of an oxygen atom that forms single bonds with two carbon atoms? Answer: ethers
Output: Ethers are composed of an oxygen atom that forms single bonds with two carbon atoms.