"he balance of trade is defined as A. the difference between the balance of the current account and the balance of the capital account. B. the difference between the balance of the current account and the balance of the financial account. C. the difference between the value of the goods and services a country exports and the value of the goods and services a country imports. D. the difference between the value of the goods a country exports and the value of the goods a country imports."

When cell phones were first entering the market, they were relatively large and reception was undependable. all cell phones were essentially the same. but as the technology developed, many competitors entered, introducing features unique to their phones. today, cell phones are only a small fraction of the size and weight of their predecessors. consumers can buy cell phones with color screens, cameras, internet access, daily planners, or voice activation (and any combination of these features). the history of the cell phone demonstrates what marketing trend?