Places with mild climates typically have summers and winters. hot; cold hot; cool warm; cool warm; cold

With the understanding that "cool" = "not so cold" and "warm" = "not so hot", then the correct statement would be:

Places with mild climates typically have warm summers and cool winters.

Among the choices, there are two "cool, warm" sets, so assuming that this is a typo, one of the sets is actually "warm, cool", which is the answer.

The answer is orbit around nucleus