Answer:
D
Explanation:
This my answer thanks you
In a study, the independent variable is the thing that you change to see how the change produces different results. In this study, the independent variable would be the use of nicotine.
There are many human relations skills which can help you to more willingly take on a challenging subject. Greater self-confidence is one of those for example.
Being more self-confident enables you to trust more in yourself and therefore to also think you can succeed better with more challenging topics in comparion to the scenario where you don't really think highly about yourself.
