(练习)课时分层作业3 Unit 1 Writing of the Unit-【提分教练】2023-2024学年新教材高中英语选择性必修第三册(人教版2019)

课时分层作业(三) Ⅰ．阅读理解 A Being highly connected to a strong social network has its benefits．Now a new study is showing the same goes for trees，thanks to their underground neighbors．The study is the first to show that the growth of adult trees is linked to their participation in fungal (真菌的) networks living in the forest soil．Though past research has focused on young trees，these findings give new insight into the importance of fungal networks to older trees — which are more environmentally beneficial for functions like capturing carbon． “Large trees make up the main part of the forest，so they drive what the forest is doing，” said researcher Joseph Birch，who led the study．When they live in the forest soil，fungal networks act as a sort of highway，allowing water，nutrients and compounds to flow back and forth among the trees．The network also helps nutrients flow to resource­limited trees like family units that support one another in times of stress． Cores taken from 350 Douglas firs (花旗松) showed that annual tree ring growth was related to the extent of fungal connections a tree had with other trees．They had much higher growth than those that had only a few connections．The research also showed that trees with more connections to many unique fungi had much greater growth than those with only one or two connections．“If you have this network that is helping trees grow faster，that helps capture more carbon year after year．These networks may help trees grow more steadily even as conditions become more stressful，and could even help protect them against death．” said Birch． Birch hopes his findings lead to further studies in different kinds of forests in other geographical areas，because it's likely that the connections among trees change from year to year．He said，“Knowing whether fungal networks are operating the same way in other tree species could help us factor in how we reforest areas after harvest，and it could inform how we want to plant trees to preserve these networks．” 1．In w