Ron is conducting an experiment that lasts several hours. During part of the experiment, a noisy power saw operates outside the room. Ron is concerned that responses may be influenced by the power saw instead of his independent variable. This example illustrates the potential problem of

a. instrumentation
b. testing
c. history
d. selection

c) history

Explanation:

According to the question, major issue of history can be seen in research of Ron as power saw's noise can impact response rather than independent variable.Thus, series of past event that took place before in experiment can get disturbed through noise and produce incorrect or influenced outcomes.  

Other options are incorrect because selection, testing and instrumentation are not the major issue of the scenario.Thus, the correct option is option(c).

answer; the correct answer is (travel horizontally);

answer; (true);