Final answer:
Pollen is used by evolutionary historians to study paleoclimate and track plant migration due to its preservation in the geologic record.
Step-by-step explanation:
The uses of pollen by evolutionary historians are primarily related to interpreting paleoclimate and understanding the migration of plants as climate changes. Pollen grains have a resistant outer shell that helps preserve them in the geologic record, making them valuable for studying past climates. Palynologists use fossilized pollen from sedimentary records to determine the types of plants that were present in a specific area or to track the movement of plants over time.