The correct answer is D. As levels of carbon dioxide increase, average global temperatures are increasing
Step-by-step explanation:
During the last decades, especially since the beginning of the Industrial Revolution carbon dioxide levels in the atmosphere had increased, this can be explained as changes in the manufacture processes and in society had led to extensive use of fossil fuels as well as massive deforestation. Additionally, the increase of carbon dioxide along with other gases had caused the global warming that refers to an increase in the temperature due to the heat and radiation that is trapped by greenhouse gases such as carbon dioxide, this phenomenon is causing widespread concern because it leads to changes in weather, increase of sea levels, extinction of species, among others . According to this, the one that is causing widespread concern is "As levels of carbon dioxide increase, average global temperatures are increasing".