Aresearcher who provides a certain treatment for one group and withholds treatment from a completely comparable group is using the research method.

I believe the answer is: Experimental method

Experimental method refers to the method that designed in a way to prove or refute an initial hypothesis. This can be done by controlling various variables in the experiment to find out whether there is a connection between the controlled variables with the independent variables,

answer; i believe that the correct answer is ; the eastern and western churches spoke different languages;

explanation:

may i ask what challenges?