Answer:
the Louisiana Purchase is the correct answer.
Step-by-step explanation:
The significant land development did President Jefferson made was the Louisiana Purchase.
It was bought by the president of United States Thomas Jefferson in the year 1803 and It was a land agreement among the United States and France.
The Louisiana Purchase was necessary because it provided the U.S. control port center of Orleans and the Mississippi River which was utilized by farmers to export their products and get funded.