Are you serious? Is this a 'trick' question? You don't know that silica has density greater than water? Trick Question....
I'm beginning to 'wonder' about this site. I'll bet you're stood-up by an ABC-Agency.
Who would ask kids this kind of question?
Info-miner's or 'profilers'!
Answer:
Incrementalism, theory of public policy making, according to which policies result from a process of interaction and mutual adaptation among a multiplicity of actors advocating different values, representing different interests, and possessing different information.
I think that the best answer here is the growth of cities: more people lived in cities and those people had more connection to the nation, rather than to the village only, as they saw more of the country, and got to know and interact with a lot more people than people living in urban areas.
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Answer: The Cuban Missile crisis