Tornadoes only form under certain weather conditions. There are three types of airs for a tornado to form, warm humid air close to the ground, cold air in the upper atmosphere, and hot dry air on top that form a cap.(na, 2010) Hurricanes can form tornadoes adding to their destructive power.
Genetically modified crops. Genetically modified crops (GM crops, or biotech crops) are plants used in agriculture, the DNA of which has been modified using genetic engineering techniques. In most cases the aim is to introduce a new trait to the plant which does not occur naturally in the species.
Commercial sale of genetically modified foods began in 1994, when Calgene first marketed its unsuccessful Flavr Savr delayed-ripening tomato. Most food modifications have primarily focused on cash crops in high demand by farmers such as soybean, corn, canola, and cotton.