These graphs show increases in greenhouse gasses in Earth’s atmosphere. As levels of greenhouse gasses have increased, the temperature of Earth’s surface has risen.
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Which change has most likely contributed to a rise in surface temperatures on Earth?
A.
Humans began using work-saving technologies that release carbon dioxide and methane.
B.
The president of the United States signed a law that created one of the country’s largest nature parks.
C.
Farmers increasingly use chemical fertilizers that allow nitrogen and phosphorous to enter water sources.
D.
The world birth rate dropped to less than 22 births per 1,000 people per year.
1 answer
A. Humans began using work-saving technologies that release carbon dioxide and methane.