The right answer is True.
The history of life on Earth shows a succession of fossil species during geological time, each species appearing and developing before disappearing. This is why fossils constitute an archive of earthly history and are used to establish the divisions of geological time.
To date the rock in which they are, fossils are not useful if they belong to a group or species that has had a very long life. On the other hand, those who have lived in very short time intervals are useful for dating because they represent a precise time. These fossils are called stratigraphic fossils.
To qualify as a stratigraphic fossil, a species must:
• have had a large geographic extension (allowing correlations),
• have existed for a short time at the geological time scale,
• have been abundant (a necessary condition for finding fossils)
For example, ammonites are used to date Jurassic and Cretaceous rocks.