Astheproverbgoes，manstrugglesupwards；waterflowsdownward...
问题详情：Astheproverbgoes，manstrugglesupwards；waterflowsdownwards．Waterrunsdownhillfrommountaintopstostreams，toriversandtooceans．Butdownhillisn'ttheonlywaythatwatermoves．Anewstudymeasureshowwatertravelsfrom...