Which of the Following Best Summarizes Krakoff's Account of the Effects

Multiple Choice

Which of the following best summarizes Krakoff's account of the effects of carbon dioxide (CO₂) on the planet?

A) Because carbon dioxide warms the planet by trapping heat that would otherwise escape into space, it has a strong effect on the Earth's temperature. Although we need some carbon dioxide to keep us warm, the increases in CO₂ levels since the Industrial Revolution are causing the planet to heat up.
B) Although some scientists have theorized that rising levels of CO₂ could warm the planet, there is significant scientific uncertainty about whether human CO₂ emissions will have any notable effect on the climate.
C) Carbon dioxide is an essential gas without which life on Earth would be impossible. Plants use carbon dioxide for food. Furthermore, carbon dioxide traps heat in the atmosphere, keeping the planet at a comfortable temperature.
D) Scientists have noted that the Earth's temperature has been rising over the past century. Many scientists have hypothesized that this increase in temperature is because of rising levels of carbon dioxide in the atmosphere, but there is still a lot of controversy among scientists about this hypothesis.