The research team noted whether participants' body language was bold and confident, and measured the amount of effort participants' put into the academic test.

划线部分为定语从句（省略了作宾语的which/that). 其中participants' 为错误，应作如下修改：

The research team noted whether participants' body language was bold and confident, and measured the amount of effort (that) the participants put into the academic test.