1. The problem is to identify the central idea of the passage about San Antonio and explain how the author uses supporting details to develop this central idea. 2. The central idea is the main point or message the author wants to communicate about the topic. Here, the topic is San Antonio. 3. From the passage, the central idea is that San Antonio has a remarkable and historically significant past that shaped its development into a major modern city. 4. The author supports this central idea by providing important historical details: the founding by Spanish explorers in 1691, the naming after Saint Anthony, the establishment of a fort and mission, Spanish control for 100 years, the Alamo's role in Texas independence, and Texas becoming a U.S. state. 5. These details are connected chronologically, showing the progression of San Antonio's history over time, which helps the reader understand how the city evolved. 6. Signal words like "soon," "for the next 100 years," and specific dates help organize the details in a timeline, reinforcing the historical development. Final answer: The author communicates that San Antonio's remarkable history, from its founding to its role in Texas independence, is key to understanding its importance today. The supporting details are connected in a chronological sequence to develop this central idea clearly.