Final answer:
The Olmec civilization initially based their prosperity on a combination of factors including agriculture and trade.
Step-by-step explanation:
The Olmec civilization initially based their prosperity on a combination of factors. They built aqueducts to transport water into their cities and irrigate their fields, allowing them to grow crops like maize, squash, beans, and tomatoes. Additionally, they developed a system of trade throughout Mesoamerica, which gave rise to an elite class. This combination of agricultural productivity and trade contributed to the Olmec's prosperity.