Read the blog by a student about prickly pear plants growing in Switzerland，and then answer the questions． The prickly pear is a type of cactus，which is a plant that usually grows in hot，dry desert conditions， for example in Mexico or in South America．So you might be surprised to discover that it is now spreading across mountainsides in Switzerland－land which is typically covered in snow in winter． I had to do a project last term on something to do with the environment．I couldn＇t decide what to do it on，so I spent some time browsing websites one weekend，looking for something suitable．After a while，I came across some information about the issue of prickly pears growing in Switzerland． I immediately knew l＇d found my topic，as although I hadn＇t been recently，I have fond memories of a long summer holiday there in my childhood．I contacted my uncle，who is a biologist，to see if he knew about the issue．It was news to him，but he said he would look into it for me． I wanted to know why prickly pears were a problem in Switzerland．I imagined that people walking in the hills and valleys where they are found might get hurt by them－the plants are covered in fine needle－like hairs which can stick to your skin and are difficult to remove．The plants are also spreading in areas where many people like to ski each winter．However，what is particularly concerning is that where the plants are found，they cover the soil completely．Flowers that used to be common in summer are now in danger of disappearing． How did the prickly pears end up in Switzerland in the first place？Could they have been imported by someone who was interested in new species，and wanted to try growing them on their own land？ I already knew that the plants produce fruit which is very tasty，and they have attractive flowers－ could this have tempted someone？In the end I was only able to establish the fact that the plants have been present since the late eighteenth century，so they are far from being a recent introduction， as I had originally thought． Scientists believe that a warmer climate in the mountains of Switzerland means that snow cover is diminishing－particularly down in the valleys，which in the past would have been covered with snow 23 each winter．This warmth is creating ideal conditions for the plants to spread．They can in fact tolerate low temperatures，but they need to be in a dry place and don＇t like to be covered in snow． The aim now is to try to prevent the prickly pears from spreading further，and to remove them from the areas of land which are badly affected．But judging by previous attempts，this will be far from straightforward．In one area，large quantities of the plants were cut down，and they were placed in huge piles in a forest，where it was thought that the shade and humid air would make the material decay and eventually turn into new soil．However，what scientists soon discovered was that bits of plants at the top of these piles were growing into new plants．They also found that new plants were growing back in the areas where the plants had been removed． This is clearly a serious matter，and I＇m fascinated．I＇ll definitely be keeping an eye on what happens in the future． For each question, choose the correct answer, A, B or C, and put a tick ( $$\(\checkmark\)$$ ) in the appropriate box. What is the main problem with prickly pears in Switzerland?

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