Question

The first organisms on earth appeared approximately 3.5 billion years ago and were all unicellular. multicellular organisms have only existed for about one billion years. what evolutionary milestone made it possible for more complex, multicellular organisms to exist?

Answer 1

The ability to produce food by the process of photosynthesis made it possible for the other complex organisms to thrive upon the earth. They would use the energy produced by the photosynthetic organisms. The appearance of eukaryotes further helped in laying down the foundation of the evolution of multicellular organisms.