Scientist think that all of life on earth originated from which type of organisms?

A. single-cell prokaryotes

B. single-cell eukaryotes

C. multicell animals

D. stromatolites

It's definitely a. Prokaryotes are organisms that don't have membrane bound organelles or a true a nucleus. Scientists theorize that single, cell hallophile organisms started in the primoridial soup. Through the endosymbiotic cell theory, it is believed that plastids engulfed free floating mitochondria and began the grassroots for life

B. Single-Cell Eukaryotes