According to sources one, what common feature did de Soto La Salle d'Iberville's expeditions have in common

According to source 1, the common feature that De Soto, LaSalle and D'iberville's expeditions had in common was that they all explored the Mississippi River delta.

Explanation:

Hernando de Soto, the Spanish explorer, first discovered the Mississippi River in 1540. The Spaniards for the first time saw the Mississippi River, known as the "Father of the Water" south of Memphis, Tennessee. They crossed the river and went to Arkansas and Louisiana.

Sieur de La Salle, a French explorer, was the first European to travel the length of the Mississippi River. He was sent by King Louis XIV. He travelled south from Canada and sailed down the Mississippi River to the Gulf of Mexico.

Pierre Le Moyne D'Iberville is known for exploring the northern coast of the Gulf of Mexico. He rediscovered the mouth of the Mississippi River and established a temporary fort, Fort Maurepas, on Biloxi Bay later.