The synthesis of new DNA requires the prior existence of ...

[penguins]

The synthesis of new DNA requires the prior existence of oligonucleotides to serve as primers. On Earth, these primers are small RNA molecules. This latter observation is evidence in support of the hypothesized existence of
A) a snowball Earth.
B) earlier genetic systems than those based on DNA.
C) the abiotic synthesis of organic monomers.
D) the delivery of organic matter to Earth by meteors and comets.
E) the endosymbiotic origin of mitochondria and chloroplasts.

[Millan]

I know it's B, we did this yesterday

[penguins]

Thank you, thank you!!