Final answer:
The negative effect of increased globalization during the 1990s included a widening gap between wealthy and poor nations and increased domestic economic inequality in developed countries like the United States.
Step-by-step explanation:
One negative effect of increased globalization during the 1990s is that it greatly increased inequality and the gap between wealthy and poor nations (option c). Globalization has led to an international division of labor where wealthier workers in core nations are pitted against low-wage labor in peripheral and semi-peripheral nations, exacerbating economic disparities. Furthermore, the movement of corporate manufacturing to countries with cheaper labor and weaker environmental regulations has led to a loss of well-paid jobs in developed countries such as the United States, intensifying domestic inequality. Moreover, weaker nations are often forced to open their markets to international competition while stronger nations protect their own industries, further disadvantaging the less developed countries.