[0:07]GM stands for genetically modified. So GM crops are plants grown for food whose genes have been altered using genetic engineering. In some cases, the genes of other organisms have been inserted into the genome of the crop plant to improve it in some way. As the human population increases, there is a higher demand for food. And it's often difficult to grow enough to provide everyone with a balanced diet. Growing GM crops is a partial solution to this problem, because GM crops tend to have higher yields than conventional crops. They can also offer extra nutritional value. Let's take a look at a few examples of genetically modified crops, so we can see how this is possible. Crops that are most commonly modified are cotton, soy bean, maize, and canola. Crop yields are often negatively affected because pests like insects damage the crops. Traditionally, farmers have sprayed their crops with pesticides to kill the insect pests, but this is time-consuming, expensive, and often harmful to the farm workers in contact with the poisons. Also, pesticides kill useful insects such as pollinators. It can harm other animals that eat the insects that have been poisoned. Spraying the pesticides also damages soil and water in the environment. Crops have been genetically modified with a gene from a bacterium, called Bacillus thuringiensis. This gene causes the cells of the crop plant to produce an insecticide in their leaves that kills insects that eat it. The genetic modification reduces the need for chemical pesticides. The growth of weeds in fields reduces the yield of crops, because the weeds compete with the crops for water, light, and minerals in the soil. Farmers can spray their fields with weed killers, but this may also damage the environment, or even the crop plants themselves. So crops can also be genetically modified to be resistant to weed killers. This means that only the weeds will be killed by the weed killers. This doesn't reduce the amount of chemicals sprayed on a field, but it does mean that higher yields can be gained. Have you ever been told that eating carrots helps you see in the dark? This is because carrots are a good source of vitamin A, which is essential for healthy vision. A common problem in some countries is a deficiency in vitamin A, because people have a diet mainly made up of cereals like rice, with few fresh fruits and vegetables. To overcome this vitamin A deficiency, rice has been genetically modified to contain beta-carotene, which is used in the body to make vitamin A. This gives the rice a yellow color, so it's known as golden rice. Its taste is not altered, but it contains extra nutritional benefits. Other examples of GM crops include those that grow in difficult conditions, such as drought or cold temperatures, and crops that are resistant to diseases. All of these genetic modifications mean we can either increase yields from existing farmland, or we can farm low-quality land. Both of which help us to feed the ever-growing world population. But so far, we have only looked at the benefits of growing GM crops. Many people are worried about possible risks associated with genetic engineering. For example, little is known about the long-term effects of genetic engineering, as GM crops haven't yet been around for long. There are concerns that GM crops could breed with other plants, which would spread the modified genes into other populations, and this could have a negative impact on whole ecosystems. These risks are the reason why growing GM crops is banned in many countries. Many people think that more research needs to be done to make sure they're safe. So to recap, genetically modified crops can help with increasing the amount of food grown. Research is being done all the time to investigate possible risks to human health and the environment. Although many people have opinions about genetic engineering and GM crops, we need to ensure that our knowledge is informed by reliable scientific research conducted by many different scientists.
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