Answer:
The French explorer that sailed down the Mississippi River to the Gulf of Mexico was Rene Robert Cavelier de La Salle.
Explanation:
La Salle emigrated to Canada in 1666, where he lived as a fur trader. He made repeated expeditions to the furry land around and south of the Great Lakes and reached Ohio. Nearly lined up with the colonial governor Louis de Buade de Frontenac, on a visit to France, he succeeded Louis XIV's support for continued colonization in the country south of the Great Lakes. In 1679 he started a large expedition and departed from Cakade to the south, exploring the country around Illinois. In 1682, he reached the Mississippi and its estuary in the Gulf of Mexico and proclaimed all these great lands as French possession under the name of Louisiana.
