Final answer:
The population of Texas changed during the Mexican National Era due to increased Anglo-American immigration facilitated by empresarios.
Step-by-step explanation:
The population of Texas changed during the Mexican National Era due to the efforts of empresarios through increased Anglo-American immigration. Empresarios were individuals who brought settlers to Texas in exchange for land grants. The Mexican government passed laws to facilitate assimilation of the Americans into Mexican society, but these efforts failed and tensions emerged between the Mexican government and the Texans. The growing American presence in Texas, their cultural and political differences from the Mexican population, and their economic activities, including slavery, contributed to the changing population dynamics.