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.

Ex Input:
Question: Adulthood is divided into how many stages? Answer: three

Ex Output:
Adulthood is divided into three stages.

Ex Input:
Question: When does exchange of dna segments happen between non-sister chromatids of homologous chromosomes? Answer: during crossing-over

Ex Output:
Exchange of dna segments happens between non-sister chromatids of homologous chromosomes during crossing-over.

Ex Input:
Question: What occurs if oxygen cannot be obtained at a sufficient rate? Answer: anaerobic respiration

Ex Output:
Anaerobic respiration occurs if oxygen cannot be obtained at a sufficient rate.