Some farmers believe that growing ____that have been ____is a good way to ____ pests and improve the quality of their produce. However, this type of ____has both advantages and disadvantages. One of the advantages is that farmers can grow plants that produce a poison that is harmful to ____. This means that farmers will not have to use ____ and so this should be better for the surrounding environment and the ____. As a result, it could help to protect other ____as well as the ____ of any animals in the area. On the other hand, farmers usually only spray their fields once or twice per year but these new plants would be toxic all year round. Furthermore, it is possible that over time the pests may ____by the toxins and so the problem would be worse than ever. The toxins may also be poisonous to other plants and animals and this would upset the ____and may lead to more animals becoming ____

U9 The natural world

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