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LifeScience sec8

this becan whn the eath originated 4.6 billion years ago,and continued until about 540 million years ago. Precambrian time
the first true cells were called prokaryotes
prokaryotes are cells that pack a nucleus
early prokaryotic cells were anaerob
prokaryotic organisms were called cyanobacteria
cyanobacteria are pjotosynthetic organisms
as cyanobacteria carried out photosynthis they released oxygen gas into oceans
the upper atmosphere is called the ozone
uv radiation can damage DNA
Created by: OMG_Elmo