GROWTH DEVELOPMENT CHILD
FORMATIVE ASSESSMENT
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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widespread geographically, long lifespan
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widespread geographically, short lifespan
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specific place, long lifespan
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specific place, short lifespan
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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: -Because they were mobile animals, they tended to inhabit large, even global areas. They were also hard-shelled invertebrates, so they fossilized easily. These fossils are large enough to study without a microscope.
Detailed explanation-3: -Thus, index fossil is an abundant and easily identifiable fossil with a wide geographic distribution and a short geologic range.
Detailed explanation-4: -Rock layers containing trilobite fossils must be that age. Different species of trilobite fossils can be used to narrow the age even more. Trilobites are good index fossils.
Detailed explanation-5: -They are useful in this way because the index fossil species only lived for a short period of geological time, which still may be several million years. Knowing the span of time that species lived, geologists know the rock strata where the fossils were found must also have formed during this span of time.