Question

question: what type of fossils must be known to be from a specific time period, exist in abundance, and be easily found and identified to be used? answer options: select one of four magnetic fossils encasement fossils index fossils impression fossils

Explanation:

Index fossils are defined as fossils that are from a specific time period, exist in abundance, and are easily found and identified. Magnetic fossils relate to magnetic properties, encasement fossils refer to a type of preservation, and impression fossils are a fossil type based on impressions, none matching the given criteria as index fossils do.

Answer:

Index fossils