Coralreefs(珊瑚礁)arenotjustbeautifultolookat，butalsoveryu...
问题详情：Coralreefs(珊瑚礁)arenotjustbeautifultolookat，butalsoveryuseful．Theyshelternearly25％ofoceanlifeandprovidefoodforbillionsofpeople．However,likemanyotherspecies，thisamazingecosystem(生态系统)isindange...