EARTH SCIENCE
FOSSILS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Index fossils lived for a short period of time.
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Index fossils lived all around the world.
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Index fossils can be used to date rock layers.
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Index fossils were all from the Precambrian time period.
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Detailed explanation-1: -A useful index fossil must be distinctive or easily recognizable, abundant, and have a wide geographic distribution and a short range through time.
Detailed explanation-2: -Ammonites, trilobites, and graptolites are often used as index fossils, as are various microfossils, or fossils of microscopic organisms. Fossils of animals that drifted in the upper layers of the ocean are particularly useful as index fossils, as they may be distributed all over the world.
Detailed explanation-3: -There are some types of index fossils which include Ammonites, Brachiopods, Graptolites, Nanofossils and Trilobites.
Detailed explanation-4: -Index fossils are used to define geological periods. These fossils can be defined as “commonly found, widely distributed fossils that are limited in time span.” If one finds an index fossil in a given layer, then one has bounds on the age of the layer. Using index fossils, the geological periods are defined.