This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mutations & Codons, Subject name: Biochemistry
Silent mutations occurs because codon is : 
Select and explain. 
A. Non overlapping, B. Commaless, C. Universal, D. Degenerate
D: Degenerate
Answer: D: Degenerate 
Explanation: Degenerate Silent mutations occurs because codon is degenerate. Degeneracy/Redundancy is a propey of codons that each amino acid is having more than one codons. Silent mutations means a codon is replaced by another codon, which is coding for same amino acid.