Theoceanbottom,aregionnearly2.5timesgreaterthanthetotal...
问题详情：Theoceanbottom,aregionnearly2.5timesgreaterthanthetotallandareaoftheEarth,iseventodaylargelyunexplored.Untilaboutacenturyago,thedeep-oceanfloorwascompletelyinaccessibleandhiddenbeneathwatersav...