Certain fossils, called index fossils, help geologists match rock layers. To be useful as an index fossil, a fossil must be widely distributed and represent a type of organism that existed for a brief time period. Index fossils are useful because they tell the relative ages of the rock layers in which they occur.
Answer:
Mammals first appeared
Explanation:
The dinosaurs became extinct one million years after the Cenozoic era started. The mammals first appeared as the modern culture first appeared in that era.
The shirt is soft
and red: Qualitative
It is 72 degrees
Fahrenheit outside: Qualitative
The river flows more
quickly in the spring
than in the summer: Quantitative
There are eight elephants
over the age of six: Qualitative
The answer is c mediastinum
