In 1845, a deadly disease struck the farms of Ireland, killing all the Lumper potato plants. In another place or time, the death of a single (1)________ species might not have been so important. But in Ireland, in 1845, people depended almost (2)________on the potato for food. The death of one species caused a terrible famine. Now, some scientists are worried that such a famine could happen again----but on a much wider (3)________. Over the centruies, 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. Meanwhile, thousands of other species are becoming (4)________. For example, in the Philippines, there were once thousands of (5)________ of rice; now fewer than 100 are grown there. In China, 90 percent of the wheat varieties grown just a century ago have disappeared. Experts 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 preserve the seeds of as many different plant varieties as we can before they disappear. The idea was first (6)________ by Russian scientist Nikolay Vavilov. In the 1920s and '30s, he collected around 400,000 seeds from five (7)________. More recently, others are continuing the work he began. In the U.S. state of lowa, Diane Ott Whealy wanted to preserve (8)________ 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 (9)________ that haven't been grown for years. These food species are not just special in terms of appearance or (10)________. They also offer farmers food solutions for the future, from the past.