A research instrument that is used to gather data and information from respondents in a uniform manner through the administration of a predefined and structured set of questions and possible responses is called a(n):

Survey

Explanation:

A survey is a research instrument that is used to gather data and information from respondents in a uniform manner through the administration of a predefined and structured set of questions and possible responses.

The survey usually contains sets of questions and given to random or a group of people to fill in order to access and process the information gotten which are then used for various studies.

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.        

explanation:

may i ask what challenges?