如何分析or that serve to...?

有一读者问： 在阅读时遇到如下难解的句子：

Test questions are reviewed to eliminate language, symbols, or content considered to be potentially offensive or inappropriate for major subgroups of the test-taking population or that serve to perpetuate any negative attitudes about these subgroups.

不知其中that指的是什么？

在此句中，language, symbols, or content这个名词短语之后有两个定语： 一是过去分词短语considered to be potentially offensive or inappropriate for major subgroups of the test-taking population，另一是that从句。二者由等立连词or所连接。that在此是一关系代词。