Final answer:
The radiative zone of the Sun is the layer above the core where energy is predominantly transported by radiative diffusion until it reaches about 70% of the way to the surface, after which convection takes over.
Step-by-step explanation:
The radiative zone is a region located above the core inside the Sun, where energy is transported primarily by radiative diffusion. This zone extends from about 25% of the distance to the solar surface and reaches up until approximately 70% of the way to the surface. The energy produced in the core, primarily through the fusion of hydrogen into helium, is carried outward through this dense area. Photons, or particles of light, are repeatedly absorbed and re-emitted by the particles within this zone, which slows down the energy transfer significantly. Beyond the radiative zone, the outermost layer called the convective zone takes over, where energy is carried to the surface by the movement of hot plasma in large convection cells.