GM crops can protect the environment because they are kinder to nature. Many farmers today depend on chemicals such as pesticides, herbicides, and fertilizers to make their crops grow. Through gene biology, the genes of plants can be modified so that they will be diseases-resistant and pest-resistant and still produce the same amount. The most common GM crops grown at the moment are those that resist herbicides. The second most common are those crops that kill pests. Some crops have been grown with both these Genes. If a crop can resist herbicides, the farmer can spray a field with herbicides without harming the crop. All the weeds and other plants die, but the crop does not. By decreasing the number of weeds, the farmer increases the amount of crop grown. A good example of such a crop is GM cotton, which is often grown in the United States for cottonseed oil. If a crop can kill pests, the farmer does not have to spray so often to kill pests. An example of a pests-resistans crop is maize, which is similar to corn. There is a bacterium in the soil which produces a poison that kills insects, but it is harmless to people. Putting this bacterium gene into maize plants makes them produce their own poison, which kills the pests that eat them. This is better for the environment because it reduces the need to spray fields with pesticides and fertilizers.