One of the greatest incentives behind the reason why people who live in the least industrialized nations have more children is

here are five steps to a strong outline:

choose your topic and establish your purpose. a lot of writers struggle to define the initial focus for their paper.

create a list of main ideas. this is the brainstorming part of the writing process.

organize your main ideas.

flush out your main points.

review and adjust.

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.