Teosinte is the wild ancestor of which vital South American crop?
Teosinte is a species of grass native to Mexico, Guatemala, Nicaragua, and Honduras. It is the ancestor of modern corn, also known as maize, and it was first domesticated around 6,000 years ago. Over time, teosinte, which has small ears only two to three inches long, with just five to 12 kernels, was selectively bred to create the corn we know and love today. Modern corn has ears around 12 inches long, which generally contain more than 500 kernels.
Source: Britannica