Final answer:
It is true that in the 1700s, Spanish North America had a small population concentrated in isolated urban clusters in Florida, Texas, and New Mexico. These areas were sparsely populated and presented challenges in governance for the Spanish authorities.
Step-by-step explanation:
The statement that by the 1700s, the population of Spanish North America was small, consisting of a few, isolated urban clusters in Florida, Texas, and New Mexico is True. During this period, North America was largely dominated by English and French settlers along the east coast, while Spanish influence was more pronounced in the southwest, coming from Mexico. Spanish Florida was sparsely populated and hard to control, being far from Mexico City and Madrid. This made the region somewhat vulnerable and difficult for the Spanish government to administer effectively. Additionally, the influence of the Spanish is still evident in American culture in the southern regions of the United States today. Regarding other parts of the question, the southeastern United States was one of the world's independent centers for plant domestication, which is True. Also, recruiting native allies was crucial in the Spanish conquest of the Aztecs, which is also True. Finally, reconquering the Iberian Peninsula was indeed a military and religious action for the Spanish, which is True.