Corn on the cob
Corn is a kind of seed, like rice, that comes originally from a kind of wild grass that grows in Mexico called teosinte. It has lots of carbohydrates, but not as much protein as wheat or barley. Corn also has some vitamins, especially Vitamin B and Vitamin C.
People first began to farm corn (instead of picking it wild) around 7,500 BC in Mexico, a little later than they started to farm squash and avocados. Gradually people bred the corn plants to have more and more corn - bigger ears, with more kernels, and easier to eat - and fewer leaves. By about 1 AD, the Pueblo people in North America also grew corn.
People ate corn fresh when it ripened in summertime, by roasting or boiling the ears, or by making popcorn, but mostly they dried the kernels and crushed them into cornmeal, and then used the cornmeal to make tacos or tortillas. They filled the tacos with bean mush and vegetables. That way you could store the corn and eat it all year round. Some people also stirred cornmeal into boiling water to make pudding (kind of like oatmeal).
A corn tortilla made into a taco
When Iroquois people began to grow corn further north, in the north-east part of North America, about 1000 AD, they found that the corn took too long to get ripe, and often frost killed the plant before the corn was ripe. They had to slowly adapt the plant to the northern climate by making it evolve a shorter growing season. The Iroquois ate mainly corn pudding, corn mush, or corn soup - not tacos and tortillas.
When English settlers first came to North America in the 1500s, the Iroquois and other Native Americans showed the English settlers how to grow corn too. Like the Iroquois, the English settlers ate a lot of "hasty pudding" - corn pudding. But they also made the corn into bread like the wheat bread they had eaten back home in England, which we know now as cornbread.
Today most people in North America eat a lot of corn. Some people eat cornbread. Many people eat corn that has been turned into corn syrup to sweeten things like bread or Coke or Froot Loops. But most people in this country, including modern Pueblo people, also eat corn just the way the Pueblo people did two thousand years ago, as tacos or tortillas, or as popcorn.