If presidential candidates want to use federal campaign funding, he should

Through the funding program, presidential candidates recieve federal government funds.

Such candidate should make use of the funding discreetely by using it to pay for the qualified expenses of the campaign. Also, he should use the fund to fund major party nominees in general election campaigns. Furthermore, he can assist minor party nominees who are eligible.

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.

the telephone is the answer