What characteristic does the genetic code possess?

The genetic code is characterized by redundancy, meaning that multiple codons can specify the same amino acid. This feature is vital because it provides a level of error tolerance in protein synthesis. For example, while there are 20 amino acids, there are 64 different codons (combinations of three nucleotides), which allows for several codons to correspond to the same amino acid. This redundancy helps mitigate the impact of mutations, as some changes in the DNA sequence may not alter the resultant protein due to the presence of synonymous codons that encode the same amino acid.

In contrast, the other characteristics mentioned do not fully encapsulate the essence of the genetic code. For instance, the idea that it is fixed implies that the code does not adapt or show variability, which is not consistent with the evolutionary flexibility observed in different organisms. Additionally, while the linearity of the genetic code is a real aspect, as codons are read in sequential order, it does not encapsulate the nuances that redundancy offers. The notion of exclusivity is not applicable here, as the genetic code is not exclusive to certain sequences but is a widespread feature across various forms of life.