Adam Rutherford meets a new creature created by American scientists - the spider-goat. It is part goat, part spider, and its milk can be used to create artificial spider's web.　　It is part of a new field of research, synthetic biology, with a radical aim: to break down nature into spare parts so that we can rebuild it however we please.　　This technology is already being used to m..每个人心中都有一片海，需要自己去航行和探索。