What will our world be like in 2020 We aren't quite sure, but it's interesting to make some predictions.

    Languages

    English should still be the most popular language, but Chinese should be the second. Now, many foreign people are studying Chinese as their second language.

    Water

    Water will become as expensive as oil because many rivers will disappear. We will have to save water and pay more for clean water.

     Education

     More students will study online. Students from all over the world may study together on the Internet.

C

    Do you have brown hair? Are you taller than other kids your age? These characteristics were decided before you were born. You got your traits from your parents. They passed their traits on to you through genes (基因).

    Genes carry codes (代码) for blue eyes or brown eyes. Genes say how tall you will get and what color hair you will have. You got half of your genes from your mother. You got half of your genes from your father. So you have your own set of genes. Each person gets different genes for each body part. That is why you look like but not exactly like your brother or sister.

    A dominant (显性的)  gene shows up most of the time. Brown eyes are dominant over bluc eyes. A recessive (降性的)  gene shows up less often. Light hair comes from a recessive gene. Dark hair is more common. Look at the eye color and hair color of the people around you. You will see that this is true.

    Genes help to make you who you are. But they don't tell the whole story. Your genes may help you to be fast and strong. But you still need to learn how to run or swim or skate well.

    Many people travel to different places in the world by air. Usually it takes a long time, perhaps half a day, for passengers to stay in the plan. So airlines（航空公司）offer passengers food. But it is common that they feel bad about food taste. Do you agree?

    To solve this problem, airlines try hard to improve their food. They would like to do so because they don't want to lose customers.

    However, according to scientific research, part of the reason why plane food tastes bad is that at high altitude（海拔）we can not taste things as well as we do on the ground. Also scientists have found that our noses become very dry even before a plane takes off. As the plane moves up, the change in air  pressure（气压）reduces one third of the sensibility（感觉）of our taste buds（味蕾）. So our taste buds become senseless. The sad face, however, is that our noses don't know it.

    All of these help explain why food on the plane tastes so bad. They also help explain why airlines choose to offer passengers salty and spicy（辛辣的）food. Without doing so, the food would be tasteless.

    Now there are many researches on this. According to one of them, some volunteers are asked to lie with their feet higher than their heads for weeks. And scientists write down their feelings about food taste.

    Though scientists try their best, it is not as easy as they thought. Because they can't deal with the special environment successfully, such as the change in air pressure, making food taste good is still hard for them.

    In 1845, a deadly disease struck the farms of Ireland, killing all the Lumper potato plants. In another place or time, the death of single crop species (物种) might not have been so important. But in Ireland, in 1845, people depended almost solely on the potato for food. The death of one species caused a terrible famine(饥荒). Now, some scientists are worried that such a famine could happen again, but on a much wider scale.

    Over the centuries, farmers have discovered thousands of different species of food crops. Each species has special qualities. Some can be grown in very hot or cold climates. Others are not affected by certain diseases. However, you won't find many of these species in your local supermarket. To feed the seven billion people on Earth, most farmers today are growing only species of plants and farming only species of animals that are easy to produce in large numbers.

    For example, in the Philippines, there were once thousands of varieties of rice: now fewer than 100 are grown there. In China, 90 percent of the wheat varieties grown just a century ago have disappeared. Scientists believe that over the past century, we have allowed more than half of the world's food varieties to disappear.

    One solution to this problem is to collect and store the seeds (种子) as many different plant varieties as we can before they disappear. The idea was first suggested by Russian scientist Nikolay Vavilov. In the 1920s and 1930s, he collected around 400,000 seeds from five contients. More recently, others are continuing the work he began.

    In the U.S. state of Iowa, Diane Ott Whealy wanted to protect historic plant varieties, like the seeds her great –grandfather brought to the U.S. from Germany more than a hundred years ago. She and her husband started a place called Heritage Farm, where people can store and trade seeds.

    More importantly, the people at Heritage Farm don't just store the seeds; they plant them. By doing this, they are reintroducing foods into the marketplace that haven't been grown for years. These food species are not just special in terms of appearance or taste. They also offer farmers food solutions for the future, from the past.