the answer is a basalt rock.
Answer:
Using the real system might mess up and using a computer model is clearer and gives a more advanced view
This is an experiment where the researcher manipulates one variable, and control/randomizes the rest of the variables. It has a control group, the subjects have been randomly assigned between the groups, and the researcher only tests one effect at a time.
Answer:
The physical stimulus is the only part of the test that is measureable, and therefore, knowable. The stimulus is our anchor for our estimate of the listener's perception.
I think that it is atmosphere but not 100% sure you might want to double check
