I am going with x-rays; it is the most visible to the naked eye out of all the choices.
Answer:
EXERCISE
Explanation:
In an experiment, the independent variable is the variable that the experimenter changes or manipulates in order to bring about a measurable outcome.
In this case, an experiment is carried out to test the hypothesis that "exercise will affect the number of times a person can squeeze a clothespin in a certain amount of time". The experiment contained two groups (one group sits quietly before squeezing a clothespin as many times as possible and the other does 25 JUMPING JACKS before squeezing a clothespin as many times as possible).
The independent variable is the EXERCISE (jumping jacks) that was changed for each group in the experiment.
The major features of
schizoaffective disorder which clearly delineate it from schizophrenia are marked
symptoms of schizophrenia coupled with major depressive episode or manic
episode. Both schizoaffective disorder and schizophrenia are primary psychotic
disorders.