Eastern boundary currents are associated with the cooling off of the ocean waters. These currents originate from both of the poles, they bring cold, shallow, slow water towards the lower latitudes and cools of the water near the Equator. Once there they are warming up and move in the opposite direction as westward warm currents.
Answer:
The answer is Option C: Index fossils.
Explanation:
Index fossils are used to identify geologic periods or faunal stages in rock layers. These fossils must have a wide geographic distribution and manifest obvious evolutionary trends to help geologists and others who need this geological data to better understand the time scale and to pinpoint a time period. For example, ammonites were common during the Mesozoic Era, but they were extinct by the Cretaceous period. Geologists would use ammonites to help determine this time frame if present.
