Final answer:
The best primary source to understand the four natural regions in Texas is an agricultural worker who has lived in all four regions, due to their comprehensive knowledge. Additionally, the key differences between American settlers and Tejanos in Texas were related to slavery and religious practices.
Step-by-step explanation:
To understand the four natural regions in Texas, the best primary source would be D) An agricultural worker who has lived in all four regions. An agricultural worker with this experience would have first-hand knowledge of the climate, soil, and environmental conditions unique to each region, which are key factors in farming and impact the development of these areas. This worker's personal observations and experiences would provide a comprehensive understanding of the natural distinctions and cultural patterns associated with each region. They could offer insights into how these factors have influenced innovation and diffusion within the agricultural sectors based on Johann von Thünen's model of land use and economics.
Regarding the differences between American settlers and Tejanos in Texas, the correct answer is D) A and B. American settlers were typically unlike Tejanos in that many were slave owners, and they remained religiously distinct from the predominantly Roman Catholic Tejanos. These settlers did not generally advocate for popular sovereignty for all, including women, which makes C) an incorrect choice and E) (all of the above) also incorrect.