Who developed a heliocentric model with elliptical orbits?

the following sets of characteristics describe what we know about the outer plants is c. rocky surface, closet to the sun and larger in size

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.

a. themes: sub fields