(a) Explain, in detail, why winter temperatures are cooler than summer temperatures. Refer to
the position of the Earth relative to the position of the Sun.

(It’s to do with earth , sun , moon not geography )

because the center-south is called the heart of the country

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.