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.
--------
Question: Question: What substance is created when a copper turns from reddish brown to greenish brown? Answer: copper oxide

Answer: Copper oxide substance is created when a copper turns from reddish brown to greenish brown.

Question: Question: Plant cells have structures that animal cells? Answer: lack

Answer: Plant cells have structures that animal cells lack.

Question: Question: What is the rate at which a specific allele appears within a population called? Answer: allele frequecy

Answer:
Allele frequecy is the rate at which a specific allele appears within a population.