This was because the experiment showed that a substance could emit radiation even while it was not exposed to light.
The CH4 molecule has the lowest molecular weight, so it has the lowest boiling point.
Hope I helped :)
A controlled variable is the one that is kept constant, the manipulated variable is the independent variable in an experiment , it is called manipulated because is the one that can be changed. A responding variable or variables are the dependent variables that change as a result of the changes in the manipulated variable.
The answer is B . Brønsted-Lowry Acid/bases trade H+
