Answer:
B:index fossil
Explanation:
The trilobite fossils are examples of index fossils.
Index fossils are most desirable for stratigraphic construction and to predict ancient life forms on earth.
- Index fossils are fossils with the following characteristics;
- They have short stratigraphic span
- They have a wide geographic distribution
- Shows rapid evolutionary trends or changes.
Trilobite is one of such fossils that have the above listed properties.
