This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory chain, Subject name: Biochemistry
The comparison of the amino acid sequence of Cytochrome C different species shows many variations. Most of these variations are found 
Select and explain. 
A. Randomly, B. Only in helical regions, C. Only in strand regions, D. Mainly in loop regions
A: Randomly
Answer: A: Randomly 
Explanation: Reference satyanarayana 4e