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What is Geologic Time?

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Geologic Time refers to the vast time scale used by geologists and paleontologists to describe the timing and relationships of events in Earth's history.

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What is a half-life in radioactive decay?

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Half-life is the time required for half of the radioactive atoms in a sample to decay into a different element or isotope.

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What is the significance of stromatolites in Earth's history?

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Stromatolites are layered structures created by the activity of microorganisms, particularly cyanobacteria, and are among the oldest evidence of life on Earth.

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What major event marks the end of the Precambrian era?

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The appearance of fossilized organisms with hard body structures, such as shells and bones, marks the end of the Precambrian era.

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What evidence supports the meteorite impact theory for the extinction of dinosaurs?

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The presence of iridium in rock layers dating to 66.4 million years ago, which is also found in meteorites, supports the meteorite impact theory.

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What is the order of rock layers in a geological cross-section?

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In an undisturbed geological cross-section, the oldest rock layers are at the bottom, and the youngest are at the top.

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What is the Cenozoic Era?

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The Cenozoic Era is the most recent geological era, beginning 66 million years ago, characterized by the dominance of mammals and birds.

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What is the Mesozoic Era known for?

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The Mesozoic Era, often called the Age of Reptiles, is known for the dominance of dinosaurs and the emergence of mammals and birds.

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What are the four main divisions of the Geologic Time Scale?

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The four main divisions are Eons, Eras, Periods, and Epochs.

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What is relative dating in geology?

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Relative dating is a method used to determine the age of rocks and fossils in relation to one another, without determining their exact age.