Oxygen levels start to decline from 35 percent down to today's levels D. After the Carboniferous period
<h3>Further explanation
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Oxygen levels started to decline from 35 percent down to today's levels about 95 million years ago.
The Carboniferous is a geologic period and system that spans 60 million years from the end of the Devonian Period 358.9 million years ago, to the beginning of the Permian Period, 298.9 Mya. The Carboniferous is occurred 358.9 (+/- 0.4) million years ago - 298.9 (+/- 0.15) million years ago
Whereas the Permian spans 47 million years from the end of the Carboniferous period 298.9 million years ago, to the beginning of the Triassic period 251.902 Mya. It occurred 298.9 (+/- 0.15) million years ago - 251.902 (+/- 0.024) million years ago
The Triassic spans 50.6 million years from the end of the Permian Period 251.9 million years ago, to the beginning of the Jurassic Period 201.3 Mya. Triassic occurred 251.902 (+/- 0.024) million years ago - 201.3 (+/- 0.2) million years ago
The Silurian is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago, to the beginning of the Devonian Period, 419.2 Mya. It occured 443.8 (+/- 1.5) million years ago - 419.2 (+/- 3.2) million years ago
Therefore, D. After the Carboniferous period, oxygen levels started to decline from 35 percent down to today's levels
<h3>Learn more</h3>
- Learn more about oxygen levels brainly.com/question/11494449
- Learn more about the Silurian period brainly.com/question/882157
- Learn more
about the Carboniferous period brainly.com/question/8930188
<h3>Answer details</h3>
Grade: 9
Subject: biology
Chapter: period
Keywords: oxygen levels, the Silurian period, the Carboniferous period, the Permian period, the Triassic period