To solve this problem, we need to identify which feature of the genetic code allows bacteria to produce human insulin using recombinant DNA technology. Let's analyze each option:$\newline \bullet$Option 1: Genetic code is not ambiguous.$\newline$ - This means that each codon specifies only one amino acid. While important, it does not directly relate to the ability of bacteria to produce human proteins.$\newline \bullet$Option 2: Genetic code is redundant.$\newline$ - Redundancy means that multiple codons can code for the same amino acid. This feature helps in minimizing the effects of mutations but is not directly related to the production of human proteins in bacteria.$\newline \bullet$Option 3: Genetic code is nearly universal.$\newline$ - The universality of the genetic code means that the same codons specify the same amino acids across most organisms, including humans and bacteria.$\newline$ - This universality allows for the expression of human genes in bacterial cells, enabling bacteria to produce human proteins like insulin.$\newline \bullet$Option 4: Genetic code is specific.$\newline$ - Specificity refers to the precise pairing of codons with their corresponding amino acids. While important, it does not explain the cross-species expression of genes.$\newline$The feature that allows bacteria to produce human insulin is the nearly universal nature of the genetic code.$\newline$Therefore, the correct option is Option 3.