The Welch family has saved some money. They can spend it on a vacation to the Grand Canyon or build a swimming pool in their back yard. They decide to spend the money on a swimming pool. What is the opportunity cost of their decision?

what words? are you talking about to complet what sentence

for many centuries there were important factors which the economies of the muslim empires developed increasingly. they applied economic procedures in production, investment, finance, taxation and property. they used to tax certain goods (for example: harvest), they charged interest on money lent, they signed contracts with merchants; they relied on a common currency, and they used checks as well as promissory notes. with the money collected by means of taxation, the government provided the needy with an income. in addition, trading networks covered huge distances, so far regions started to have contact and exchange goods. this trade network covered areas of asia, africa and europe.

answer; dead end or culdesac;