Maize is the domesticated form of a wild grass which exists in the Mexican highlands. While maize is growing, the ears are covered by the leaves. The ears don't appear until the plant is fully developed. Unless the soil remains wet, maize will die. When it is ground into flour, maize produces more flour than wheat does.
It was 10,000 years ago that the domestication of maize started. It became the main food of many of the American cultures before the arrival of the Spanish, the Europeans who first conquered the Americas. It was these Europeans who introduced maize to the rest of the world. In the Americas, the Spanish took the best land for their own imported food crops. This left the native people with poor land for maize production. In independent Mexico today, the best land is still not used for maize. Maize will no longer be widely farmed in Mexico when full free trade begins with the US. If people in developing countries, like Mexico, didn't have to plant their maize so close together because of a land shortage, they would get more than one ear to each plant. There are many countries where maize is major food. Most Mexican meals contain maize in them. One type of maize will pop when it is heated. This popcorn was first developed in ancient times. It used to be flavoured with dried herbs and spices.
We learn from the passage that in Mexico ........ .
It is clear from the passage that maize ........ .
It is implied in the passage that Mexico ........ .
We can understand from the passage that the Spanish ........ .