Answer:
Ammonites, , Brachiopod, Grapolithina, Trilobites and Nanofossils are examples of index fossils
Explanation:
Ammonites were common during the Mesozoic Era (245 to 65 mya), but were not found after the Cretaceous period. They went extinct during the K-T extinction (65 mya)
Brachiopods which are mollusk-like marine animals appeared during the Cambrian (540 to 500 mya). Some types of them still survive
Grapolithina which are widespread colonial marine hemichordates that also lived during the Cambrian period.
Nanofossils are microscopic fossils which are remains of calcareous nannoplankton, coccolithophores from various eras
Trilobites were common during the Paleozoic Era (540 to 245 mya); about half of the Paleozoic fossils are Trilobites. Trilobites evolved at the beginning of the Paleozoic Era and went extinct somewhere in the late Permian period which was 248 million years ago
This might be extra information but i hope it helps
