How is illinois considered a formal region?

A formal region is a region united by a certain trait - boundaries, culture, or economics. Illinois is considered a formal region because it has statehood. It is united by its borders, being the Illinois borders. Hey

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explanation:

radiative zone

explanation    

radiative zone is the layer of the sun which energy is transferred away from the core by radiation. although, the core is the only part of the sun that produces an appreciable amount of heat through fusion. in fact, 99% of the energy produced by the sun takes place within 24% of the sun's radius.