Global warming is arguably the greatest cause of impact to the environment, the largest of causes emanating through CO₂ levels from respiration to more detrimental causes like burning fossil fuels and deforestation. Humans are consistently increasing CO₂ levels globally- every year. The highest level of CO₂ in recorded history before 1950 was about 300 parts per million. However, current measurements of CO₂ levels have exceeded above 400 PPM, abolishing every record dating back 400,000 years . The increase of CO₂ emissions has contributed to the planet's average temperature increasing almost a whole degree.Which would be the largest contributor to the rise in Global temperatures?

a. Collectively, the gases -- water vapor, nitrous oxide, methane, and carbon dioxide-- are one of the largest contributors to global warming. b. The astronomical number of plastic wastes is the greatest cause and directly proportional to an increase in global warming.
c. Cows passing gas is not only a contributor to climate change but also the greatest cause to an increase in warmer global temperatures. d. Car emissions do contribute to global warming.