Cultural convergence is the intermixing of cultures from around the world. For decades, the most popular and best selling condiment in the United States has been ketchup. Within the last decade, salsa has become the most popular condiment sold. What explains this change among Americans?

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.