Coralreefs(珊瑚礁)arenotjustbeautifultolookat，butalsoveryu...
問題詳情：Coralreefs(珊瑚礁)arenotjustbeautifultolookat，butalsoveryuseful．Theyshelternearly25％ofoceanlifeandprovidefoodforbillionsofpeople．However,likemanyotherspecies，thisamazingecosystem(生態系統)isindange...