is a geological time period distinguished by vast deposits of organic matter in lowland swamps and other wetland areas which gave way to the formation of coal beds.

they were destroyed coming out of the civil war but after he war they were booming. if you need an in-depth answer follow up with me  

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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.