Stromatolites (pictured here) are rocky structures that generally form in shallow waters from the binding of sediment by microbial biofilms. stromatolites are typically hypothesized to be formed from the presence of cells that bind these grains together. if the appearance of the stromatolites in the fossil record were to indicate the emergence of life on earth, which cell types would most likely be responsible for their formation? a) prokaryotic cells b) eukaryotic yeast cells c) eukaryotic plant cells d) eukaryotic animal cells