Cyanobacteria were very simple organisms and performed were an role in changing Earth's early atmosphere. They carried out photosynthesis to produce the materials they needed to grow. In this process, they release Oxygen which is needed to sustain life on Earth for Humans and other organisms.
"simple aerobic bacteria"relating
to or denoting exercise that improves or is intended to improve the
efficiency of the body's cardiovascular system in absorbing and
transporting oxygen.
Answer:I think it is oxygen
Explanation:
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