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.
When farmers start growing genetically modified crops, they stop growing the old varieties. These old varieties are important sources of diverse genes that give plants other desirable characteristics. For example, a new pest or disease could come along and destroy the genetically modified rice. You are a tomato farmer whose crops are threatened by a persistent species of beetle. 2  Each year, you spend large sums of money for pesticides to protect your crops. 3  A biotechnology company introduces a new strain of tomato plant that produces a natural pesticide, making it resistant to the beetle.