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
Clusters of twisted strands of β sheet are called 
Select and explain. 
A. Amphiphatic helices, B. β barrels, C. Loops and bends, D. Supersecondary structures
B: β barrels
Answer: B: β barrels 
Explanation: Most β sheets are not perfectly flat but tend to have a right-handed twist. Clusters of twisted strands of β sheet, sometimes referred to as β barrels, form the core of many globular proteins.
Ref: Harper’s illustrated biochemistry. 30th edition page no: 39