What significant land expansions did Mexico lose as a result of the Mexican-American War?

The significant land expansions that Mexico lost as a result of the Mexican-American War include present-day California, Nevada, Arizona, New Mexico, and parts of Utah, Colorado, and Wyoming. This war, fought from 1846 to 1848, culminated in the Treaty of Guadalupe Hidalgo, which led to Mexico ceding approximately 500,000 square miles of territory to the United States. This acquisition greatly increased the size of the U.S. and facilitated westward expansion.

The other options do not pertain to the outcomes of the Mexican-American War. The Oregon Territory was acquired through a different negotiation with Great Britain, the Louisiana Purchase was a transaction in 1803 where the U.S. acquired land from France, and the Florida Territory was ceded by Spain in 1819. Thus, the correct answer reflects the specific territories that were directly impacted by the consequences of the Mexican-American War.