Question

read the passage and answer the following question(s).
determining earth’s geologic time scale
the geologic time scale is a system that scientists use to separate intervals of time in earth’s 4.5 - billion - year - old history. the time scale was formed by determining the composition, sequence, and relative age of rock layers. these data, combined with information provided by fossils, gave scientists an understanding of major events in earth’s history such as mountain formation, the first appearance of mammals, and major extinction events. today, scientists all over the world use the same sets of geologic rules and principles to determine rock relationships. scientists continue to combine rock and fossil data to better understand earth’s geological history.
use the drop - down menus to complete the statements.
choose... rocks are the most useful for scientists in determining the history of earth because they contain choose... this information, combined with the choose... allows scientists to determine the relative ages of rock layers.

Explanation:

The passage states that rock layers' composition, sequence, relative age data combined with fossil information helps scientists determine Earth's history. Fossils are the key content in rocks that provide Earth's event history, and this fossil data paired with rock data (composition/sequence/relative age) lets scientists find rock layer ages.

Answer:

Rocks are the most useful for scientists in determining the history of Earth because they contain fossils. This information, combined with the composition, sequence, and relative age of rock layers, allows scientists to determine the relative ages of rock layers.