During the evolution of life on Earth, which photosynthetic organisms were initially responsible for raising atmospheric oxygen concentrations from less than 1 percent to about 20 percent?
A. cyanobacteria
B. archaea
C. diatoms
D. flowering plants
E. mosses
Answer (3)
B or A the chapter I learned talked about both
Correct option is A. Cyanobacteria were the first photosynthetic organisms responsible for significantly increasing Earth's atmospheric oxygen concentrations, which was essential for the evolution of aerobic life.
During the evolution of life on Earth, the photosynthetic organisms initially responsible for raising atmospheric oxygen concentrations from less than 1 percent to about 20 percent were (A) cyanobacteria.
Cyanobacteria evolved from early phototrophs and began the oxygenation of the atmosphere. This critical process allowed the evolution of other life forms by increasing the oxygen concentration. Cyanobacteria, through the process of photosynthesis, played a key role in transforming the ancient anoxic atmosphere into one that could support aerobic life.
Cyanobacteria are the photosynthetic organisms that significantly increased atmospheric oxygen levels from less than 1 percent to about 20 percent. They achieved this through their process of oxygenic photosynthesis, which began over 3 billion years ago. This transformation laid the foundation for aerobic life on Earth and is known as the Great Oxygenation Event.
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