What became a major food source in Africa because of the Columbian exchange

From 1990 to 2008, by what percent did the world’s most developed economies cut their greenhouse gas emissions?

What do most climatologists see as a major cause of rising global temperatures? a. earth's closer proximity to the sun due to its gravitational pull b. greenhouse gases produced by burning fossil fuels c. rising ocean levels caused by melting polar ice sheets d. water pollution cause by industrial waste

How else might the black hand have addressed its nationalistic aspirations