This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of protein and amino acid, Subject name: Biochemistry
[{'content': 'Restriction enzymes have been found in \nSelect and explain. \nA. Bacteriophages, B. Bacteria, C. Fishes, D. Humans', 'role': 'user'}, {'content': 'Answer: B \nExplanation: A restriction enzyme or restriction endonuclease cleaves DNA into fragments at or near specific recognition sites within the molecule known as restriction sites. These enzymes are found in bacteria and provide a defence mechanism against invading viruses. Ref: Biochemistry by U. Satyanarayana 3rd edition Pgno : 579', 'role': 'assistant'}]