Cyanobacteria, once referred to as blue-green algae, has a fossil record that dates back nearly 3.5 billion years and is among the oldest fossils known. the cyanobacteria/ blue-green algae had cell walls and were photosynthetic. a few hundred years ago, this organism was classified as a plant, then as a protist. today it is classified in the eubacteria because it
a) is photosynthetic.
b) is know to be prokaryotic.
c) is the ancestor of land plants.
d) has cellulose cell walls and chloroplasts.