Cultures are similar because if they were started in the same climate as another culture they would get the same amount of rainfall and droughts which means they would produce similar crops and products. cultures could be similar if they believed in monotheism. Monotheism is the belief in one god. Two cultures could develop in the same climate, have the same crops, and yet be different. They could be different in that one culture could be monotheistic, and the other polytheistic. Polytheism is the belief in more then one god. Many European cultures are similar in that they believe in one god. However, they are different in language spoken, customs and traditions, holidays celebrated, their manner of dress, their courting and marital rituals, and diet.