Which statements about genetically engineered plants show potential benefits? 1 The increased yield from genetically engineered plants allows a smaller area of land to be farmed. 2 Genetically engineered plants may have improved nutritional value. 3 Some plants can be genetically modified to give resistance to diseases. 4 Cross-pollination with weeds could produce new varieties of weeds. 5 The use of genetically engineered crops may explain the increase in allergies in children. 6 There is more research needed on the long term effects of genetically engineered crops on the environment.