Biology, 12.12.2019 23:31, mathman783

We know that the atmosphere became more oxygen-rich around 1.8 billion years ago (ga) because of geologic evidence such as choose one:

a. redbeds that formed after 1.8 ga.

b. abundant fossils of land plants, signifying the start of photosynthesis.

c. bifs that occurred prior to 1.8 ga but disappeared from the rock record after that time.

d. the presence of abundant pyrite after 1.8 ga.

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We know that the atmosphere became more oxygen-rich around 1.8 billion years ago (ga) because of geo...