In the chain of events leading from the abiotic synthesis of biological building blocks to...

In the chain of events leading from the abiotic synthesis of biological building blocks to the evolution of eukaryotes (Figure), which transition appears to be the least characterized? Why do you think this is the case?

Synopsis of the Oparin–Haldane model The first stage would have been the formation of biological building blocks (nucleotides and amino acids) from existing inorganic material on the early Earth. Thesecond stage would have been the polymerization of these building blocks to form biological macromolecules (nucleicacids and proteins). Finally, these macromolecules would have directed the formation of other biological structures, such as cell membranes.