Answer: The percentage of serine in the hypothetical polypetide is 16%.
Explanation: Given the proportions of uracil and cytosine nucleotides 4/5 U and 1/5 C. According to probabilities, specifically permutation. We can multiply the proportions to get the probabilities of obtaining the codons. In this case for UC equivalent to serine, would be 4/5 * 1/5= 4/25 this is the same as 16% .