What causes civilizations to join together against a common enemy?

Click on  the link  to view information gathered by the organization keep america beautiful. read "the costs of american littering" to find three negative effects of litter in local communities.  based on your research, what are the negative effects of litter in local communities? check all that apply.litter cleanup is very expensive.litter has decreased since 1969.litter is a constant community problem.litter causes property in the community to be less valuable.litter contaminates water and has other environmental consequences.

Recently, there has been pressure to loosen clean air standards. use economic arguments to support or oppose this proposed action.

Which of these would be describing a developed country? a) literacy rate of 84% b) life expectancy of 58 years c) post-secondary education rate of 10% d) infant mortality rate of 3 per 1,000 births