|
Reptiles first appeared during the _____ era. |
Paleozoic |
|
We are living during the _____era. |
Cenozoic |
|
Dinosaurs went extinct during the _____. |
Mesozoic |
|
_____ were the dominant vertebrate life form during the Paleozoic era. |
Amphibians |
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Life arose during the _____. |
Precambrian |
|
Flowering plants first appeared during the _____. |
Mesozoic |
|
The Mesozoic era began approximately _____ million years ago. |
251 |
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The Precambrian time began at least _____ million years ago. |
4,600 |
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Seed plants first appeared during the _____ |
Paleozoic |
|
The first prokaryotic cells appeared during the _____. |
Precambrian |
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Animals first appeared during the _____. |
Precambrian |
|
The Cenozoic era began approximately _____ million years ago. |
65 |
|
_____ were the dominant vertebrate life form during the Mesozoic era |
Dinosaurs |
|
Most modern animal phyla evolved during the _____ era. |
Paleozoic |
|
Bony fish first evolved during the _____ . |
Paleozoic |
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How long ago do scientists believe life first began on Earth? |
3.7 billion years |
|
What process produces Earth’s atmospheric oxygen? |
photosynthesis |
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What evidence points to the date of the appearance of the first oxygen-producing organisms? |
iron oxides in rock |
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The red sedimentary rocks of Western Australia resulted from the combination of oxygen and _____. |
iron |
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Achaeans can tolerate which of the following extreme habitats? |
near-boiling water high pressure very salty water oxygen-free environments |
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Most scientists support the hypothesis that the Cretaceous mass extinction was caused by _____. |
the impact of a large meteor |
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Why were the scientists in the video studying fossil leaves? |
Plant anatomy is a good indicator of the climate. |
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What evidence do scientists use to support the meteorite impact hypothesis? |
A global layer of iridium has been dated to about the same time as the mass extinction. |
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Why do scientists think that the iridium layer is evidence of meteorite impact? |
Iridium is rare on earth and common in meteorites. |
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Scientists believe that a meteorite struck _____, leading to the extinction of dinosaurs |
Yucatan, Mexico |
|
How long ago did the dinosaurs go extinct? |
65 million years |
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