According to wallerstein's world systems theory which countries have the highest levels of economic development

From where does the solar winds generate

Which of these is a drawback of using natural gas? a. it is fairly safe for use in homes.b. it burns more cleanly than crude oil products.c. scientists have developed new ways of extracting it.d. during its extraction, groundwater can be contaminated.

The percentage of people in the united states engaged in agriculture in 2000 was approximately a. 56% b. 38% c. 21% d. 2%