Answer:
Various compounds made of different forces between molecules
Explanation:
In an experiment, the independent variable is the variable that is changed or manipulated by the experimenter in order to effect a measurable response.
According to this question, a student compares the boiling point of substances having different intermolecular forces. This means that the student uses different substances with different intermolecular forces and measures the boiling point of each, which depends on the intermolecular forced in them. Hence, the independent variable in this experiment is the VARIOUS COMPOUNDS MADE OF DIFFERENT FORCES BETWEEN MOLECULES.
