Diagram of human migration, ideas, and customs. First bubble: groups migrate in search of food, water, resources. Second bubble: Migrants meet other groups with different beliefs. Third bubble: blank. Fourth bubble: Belief systems and ideas spread. What is missing from the diagram showing the relationship among human migration, ideas, and customs?

New ideas and beliefs emerge from the different groups.
The more powerful group puts their ideas into practice.
Groups agree to live together in a separation of ideas and beliefs.
New customs and beliefs are adopted