Short answers, pulled from the story.
Central America is usually defined as seven countries: Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama. It is sometimes also taken to include Mexico, and the Dominican Republic is a full member of the Central American Integration System.
The Captaincy General of Guatemala formally ended on the 15th of September 1821 with the signing of the Act of Independence of Central America. By the 28th of September 1821, the entire region was fully independent from Spanish authority.
The Federal Republic of Central America was a sovereign state that existed from 1823 to 1840, first known as the United Provinces of Central America. It was made up of five states: Guatemala, Honduras, El Salvador, Nicaragua, and Costa Rica, and its 1824 constitution abolished slavery.
Central America rests mostly on the Caribbean Plate, which converges with the Cocos, Nazca, and North American plates to form the Middle America Trench, a major subduction zone. The region has over 70 active volcanoes, and faults such as the Motagua Fault have produced repeated large earthquakes.
Central America holds 7% of the world's biodiversity as part of the Mesoamerican biodiversity hotspot, serving as a bridge between the Nearctic and Neotropical realms. Over 300 species are threatened, including 107 classified as critically endangered.
Panama was administered as part of the Viceroyalty of Peru from 1543 and the Viceroyalty of New Granada from 1739, then belonged to Colombia and its successor states. Only after Panama seceded from Colombia on the 3rd of November 1903 did some begin to regard it as a Central American entity.