Answer:
a. They must be present in a large geographic area.
Explanation:
Index fossils can be used to determine the age of a rock strata with great precision, but they must be scattered over a large geographic area to be able to be used reliable for this type of measurement. Index fossils typically indicate a certain type of paleoenvironment belonging to a very specific prehistoric period and their formation coincides with the age of the rock layer.
Answer:
there are multiple reasons as to why death rates decrease
Environmental interventions.
improvement in nutrients.
Advances in medical medicine
advanced access to health care.
upgrades in surveillance and monitoring disease.
are just a few :)
Explanation:
I think the answer might be A
