【正确答案】 1、the child    

【答案解析】[定位] 由题干关键词team和the most important member可将答案定位至第二个小标题下第四段第二句。
[解析] The core members of the team are the foster parents，the biological parents，the court，the social worker in charge of the case and，most importantly，the child him or herself.。据此，空格里可以填入the child。