The amount of fuel used to heat and cool your home can be reduced by good

The amount of fuel used to heat and cool your home can be reduced by good insulation.

the answer is "d"

(context) if you were to travel to the middle east and go into peoples homes there would be like 4 generations in there

(more context) i'm pretty sure in the middle east they take loyalty and family bonds very serious

(last bit of context) i'm also positive that extended families are most commonly found in urban areas

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