This is a view called "group selection, " because it argues that our genes came down to us today not just because some individuals were more fit than their neighbors, but because some groups were more fit (more cohesive and cooperative) than their neighboring groups.

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Also, she advises intercultural weddings can seem more cohesive if an officiant and readers incorporate some native languages into the ceremony as a nod to family members who have traveled from another part of the world.

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It even inspired some people to think that Congress might mend its ways and become more cohesive.

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