Eachyear,about10,000to100,000animalspeciesdieoff.Theyjo...
问题详情：Eachyear,about10,000to100,000animalspeciesdieoff.Theyjointhecountlessspeciesthathavegoneextinct(灭绝)overthecourseofEarth'shistory-andextinctionmeansforever.Atleastitusedto.Scientistsarenowcl...