Respuesta :
Answer:
A trilobite could be an example of an index fossil, because they only existed for a certain period of time
Explanation:
Answer:
trilobites and ammonites
Explanation:
Trilobites are a fossil group of extinct marine animals which became extinct around 250 million years ago.
Ammonites are a extinct group of marine invertebrates. They are molluscs in the class Cephalopoda in which we also find octopuses, squids, cuttlefishes and the nautilus.