Vegetable was very dull, typically comprising mainly some staple product made from rice, rye, barley, wheat, millet or maize. The addition of vegetable matter provided some variety to the diet. The staple diet of the Aztecs in Central America was maize and they cultivated tomatoes, avocados, beans, peppers, pumpkins, squashes, peanuts, and amaranth seeds to supplement their tortillas and porridge. In Peru, the Incas subsisted on maize in the lowlands and potatoes at higher altitudes. They also used seeds from quinoa, supplementing their diet with peppers, tomatoes, and avocados. In Ancient China, rice was the staple crop in the south and
Vegetable oils as alternative energy that yields 20% more oil than the standard variety. There is concern that the current growing demand for vegetable oil is causing deforestation, with old forests being replaced with oil palms. When land is cleared it is often burned, which releases large amounts of the greenhouse gas CO. Vegetable oil production would have to increase substantially to replace gasoline and diesel. With current technology such an increase in production would have a substantial environmental impact. In some poor countries the rising price of vegetable oil is causing problems. There are those that say using a food crop for fuel sets