It is suggested that the ZnS surfaces (1) used the solar
radiation to drive carbon dioxide reduction, yielding the building blocks for
the first biopolymers, (2) served as templates for the synthesis of longer biopolymers
from simpler building blocks, and (3) prevented the first biopolymers
from photo-dissociation, by absorbing from them the excess radiation. In addition,
the UV light may have favoured the selective enrichment of photostable,
RNA-like polymers.