Final answer:
Thomas Jefferson found Native American artifacts during his excavation on his property in Virginia. He did not discover dinosaur fossils, unearth treasure, or conduct a geological survey. Additionally, as president, he sent Lewis and Clark on an expedition to explore the Louisiana Territory and find an all-water route to the Pacific Ocean.
Step-by-step explanation:
Thomas Jefferson conducted an excavation on his property in Virginia and discovered Native American artifacts. As a pioneering archaeologist, Jefferson was one of the first to document and interpret the mounds in the United States and his approach marked a systematic way of understanding past civilizations. He meticulously recorded his findings but did not find dinosaur fossils, unearth a treasure chest, or conduct a geological survey as part of his mound excavation work.
In relation to his presidency, one of Thomas Jefferson's significant actions was orchestrating the Lewis and Clark Expedition to explore the Louisiana Territory. Jefferson tasked Meriwether Lewis and William Clark with finding an all-water route to the Pacific Ocean, strengthening U.S. claims to the Pacific Northwest, exploring and mapping the new territory, cataloging its natural resources and wildlife, and establishing contact and trade with Native American tribes.