The answer is b i did the quiz
<u>Answer:</u>
Cyanobacteria start producing pure oxygen around 200 million years ago.
<u>Explanation:</u>
Many scientists believed that Earth did not have any oxygen. Cyanobacteria or the blue green algae are the microbes which produced oxygen for the first time with the help of photosynthesis. This was around 4.5 billion years ago: after Hadean eon.
They were very simple, but they produced oxygen in the early earth’s atmosphere. So, they brought evolution on earth. This “blue-green algae” exists in salt water, rocks and soils and play a major role in maintaining the ecosystem.
Only prokaryotes (the archaea<span> and the </span>bacteria<span>) reproduce asexually through binary fission. Eukaryotes (such as protists and unicellular fungi) reproduce by mitosis; most of these are also capable of sexual reproduction</span>
The major function of the large intestine is to absorb water from the remaining indigestible food matter and transmit the useless waste material from the body.