Which of the following was an effect of the crusades? a. people became more isolated in their home regions. b. christianity was limited to european countries. c. muslim advances in science and medicine spread to europe. d. trade declined because people feared violence.

An effect of the Crusades is option D, Trade declined because people feared of violence.

Explanation:

The crusades were military campaigns that were carried out by Europe, France and the Roman Empire. Their objective was to reestablish Roman apostolic control and they were carried out between 1096 and 1291. They were brought against Muslims, Jews, Cathars, Russians, Lithuanians and political enemies of the church.

Due to the violence generated, commerce declined because people feared the way things were carried out.

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.