This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'Radiolabelled  DNA  was  allowed  to  replicate twice in a non radioactive environment. Which of the following is true? \nSelect and explain. \nA. All the strands will have radioactivity, B. Half of the DNA will have no radioactivity, C. No strands will have radioactivity, D. Three–fourth of the DNA replicated will have radioactivity', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Semi conservative nature of DNA Replication proved by Meselson and Stahl states that half of the\xa0 parent strand is conserved during replication in the daughter strand.\nAfter one replication all the DNA will have radioactivity.\nAfter two replication half of the DNA will have radioactivity.\n\nRef : Harper’s illustrated biochemistry, 31st edition.', 'role': 'assistant'}]