Answer:
Prokaryotes and Eukaryotes
Explanation:
In the primitive atmospheric condition where there was less or no oxygen about 3.8 billion years back, the origin of life started from the appearance of the unicellular prokaryotes, which were characterized by the absence of a well-developed nucleus in their body. They were able to form a single cell within which they comprised the essential requirements for the survival of life.
About 600 million years back, the unicellular organisms gave rise to the formation of multicellular eukaryotes, which were comprised of a well-defined nucleus that was able to form after undergoing episodic evolutionary changes on earth. This is how the evolution of life has taken place from the primitive simple prokaryotic organisms to the modern-day complex multicellular eukaryotic organisms.
