Inglês — L. interpretação de texto - reading comprehension

READ TEXT I AND ANSWER QUESTIONS 11 TO 14: TEXT I 1 Few people would choose to farm in southern Perus  bleak Puno district. Lying between 3,800 and 5,000 m.  above sea level, Puno is prone to frequent droughts,  floods and frosts, and its shallow soils have been 5 degraded by centuries of wind and water erosion, and  more recently by overgrazing of livestock and overuse  of chemical inputs. Yields of the areas staple crop,  potato, are as low as one tonne per hectare and farmers  incomes average less than US$2.50 a day. 10 Yet Puno has become the site of an exciting experiment  in agricultural rehabilitation over the past decade,  development workers and farmers there have revived a  3,000-year-old indigenous farming system that was  abandoned in Incan times and rediscovered by 15 archaeologists. Called waru-waru, the system employs  raised platforms of soil surrounded by ditches to collect  and conserve water, leach out salts and create a warm  microclimate favourable to crops. Today, farmers have  converted more than 7,000 ha of land to waru-waru for 20 production of quinoa, barley, oats and potato. Their per  hectare potato yields range up to 10 tonnes, and per  capita incomes have more than doubled. (http://www.fao.org/ag/magazine/0211sp1.htm 27/04/04)

Yet in Yet Puno has become the site (l. 10) introduces a: