A. It is true that many of the large cap companies in the S&P 500 index have business overseas, some of them even have majority of their incomes from overseas, for example, Coca-Cola. From this sense, buying the S&P 500 index the fund has achieved some global exposure.
However, S&P 500 index only covers some of the large cap companies traded in the U.S., there are many more large companies do not trade in the U.S. Let alone thousands of middle and small foreign companies. If you want to achieve true global diversification, just S&P 500 exposure is simply not enough.