Your friend is wary of environmentalists’ claims that global warming could lead to major biological change on Earth. Which of the following statements can you use in response to your friend’s suspicions? A) We know that atmospheric carbon dioxide has increased over the past 150 years. B) Through measurements and observations, we know that CO2 levels and temperature fluctuations are directly correlated, even in prehistoric times. C) Global warming could have significant effects on agriculture in the United States. D) Sea levels will likely rise, displacing as much as 50% of the world’s human population. E) All statements listed could be used.