Asked by Nicholas Pride on Apr 23, 2024

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Upon what basis were the upper and lower boundaries of the Mesozoic Era defined?

A) dramatic changes in the color of the rocks from green to tan
B) major episodes of mountain building
C) abrupt changes in the types of fossils, representing mass extinctions
D) the discovery that a meteoroid impact may have killed the dinosaurs

Mesozoic Era

A geologic era that occurred about 252 to 66 million years ago, characterized by the dominance of dinosaurs and the appearance of flowering plants.

Mass Extinctions

Events in Earth's history when significant numbers of species disappear rapidly and irreversibly, often due to drastic environmental changes.

  • Understand how mass extinction events and major geological phenomena are recorded in the geologic timescale.
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GG
genelle gonzalez6 days ago
Final Answer :
C
Explanation :
The upper and lower boundaries of the Mesozoic Era are defined by abrupt changes in the types of fossils found, which represent mass extinctions. These changes mark significant shifts in the Earth's biological history, including the mass extinction at the end of the Cretaceous period that led to the demise of the dinosaurs.