Final answer:
The genetic code is almost universal among all known living organisms, pointing to a common ancestry for all life on Earth due to its essential role in protein synthesis.
Step-by-step explanation:
The characteristic of the genetic code that points to a common ancestry for all organisms is that the genetic code is almost universal. All known living organisms use the same genetic code, with only a few minor variations. This universality suggests that all life on Earth shares a common origin, as the genetic code serves as a fundamental basis for the translation of nucleotide sequences of RNA into the amino acid sequences of proteins during the process of translation. The fact that this code is shared by such a diverse array of organisms indicates that it was already present in the last common ancestor of all current life forms.