医生建议患甲状腺肿大的病人多食海带，这是由于海带中含有较丰富的（　　）

                                                                                               金陵驿二首（其一）
                                                                                                     文天祥
                                                                                    草合离宫转夕晖，孤云飘泊复何依！
                                                                                    山河风景元无异，城郭人民半已非。
                                                                                    满地芦花和我老，旧家燕子傍谁飞？
                                                                                    从今别却江南路，化作啼鹃带血归。