What country or region cultivated coffee yams rice and watermelon?

It's difficult to pinpoint one specific country or region that cultivated all of these crops simultaneously. Here's why:

* Different origins: Each of these crops has a different origin:

* Coffee: Native to Ethiopia.

* Yams: Originated in tropical Africa, with different species developing in different areas.

* Rice: Likely originated in the wetlands of Southeast Asia.

* Watermelon: Native to Africa, possibly originating in the Kalahari Desert.

* Spread over time: While some crops might have spread to other regions relatively quickly, others took longer to migrate across the globe.

However, we can make some educated guesses based on historical cultivation:

* Africa: It's likely that Africa played a significant role in the early cultivation of coffee, yams, and watermelon, given their origins on the continent.

* Asia: Southeast Asia was central to the development of rice agriculture and played a significant role in its spread.

It's more accurate to say that these crops were cultivated in multiple regions over long periods of history, with their spread often connected to trade and cultural exchange.