This followed criticism that the rats used in the experiment were prone to cancer anyway.
1.used不是应该用被动语态吗,这里有省略什么成份吗,如果有,麻烦详细告知是什么语法点
2.be prone to cancer anyway这里的cancer是名词,可以直接在be prone to后面加名词吗,如果可以要怎么翻译,因为be prone to的意思是:易于.,不是很理解这个的用法.