9. Another name for unicellular organisms that dominated Earth up to the Precambrian time is
A. eukaryotes.
B. cyanobacteria.
C. stromatolites.
D. prokaryotes.
D?
Yes, D.
Correct! The answer is D. prokaryotes. Now, let me explain why.
To find the correct answer, we need to understand the different terms given and their relevance to unicellular organisms that dominated Earth up to the Precambrian time.
A. Eukaryotes: Eukaryotes are organisms whose cells have a nucleus and other membrane-bound organelles. They include both single-celled organisms and multicellular organisms. While eukaryotes did exist during the Precambrian time, they were not the dominant unicellular organisms.
B. Cyanobacteria: Cyanobacteria, also known as blue-green algae, are a group of photosynthetic bacteria that obtain energy through photosynthesis. While cyanobacteria did exist during the Precambrian time, they were not the dominant unicellular organisms.
C. Stromatolites: Stromatolites are layered structures formed by cyanobacterial mats and sediment trapping. While stromatolites were abundant during the Precambrian time, they are not the name for the unicellular organisms themselves.
D. Prokaryotes: Prokaryotes are organisms whose cells do not have a nucleus or other membrane-bound organelles. They include bacteria and archaea. Prokaryotes were the dominant unicellular organisms on Earth up to the Precambrian time, making D the correct answer.
Therefore, the correct answer is D. prokaryotes.