Eachyear,about10,000to100,000animalspeciesdieoff.Theyjo...
問題詳情：Eachyear,about10,000to100,000animalspeciesdieoff.Theyjointhecountlessspeciesthathavegoneextinct(滅絕)overthecourseofEarth'shistory-andextinctionmeansforever.Atleastitusedto.Scientistsarenowcl...