- The earth 's atmosphere is made of 04 to 1 percent water vapor by volume
- Water vapor is a kind of greenhouse gas
- Therefore, water vapor is a greenhouse gas accounting for 04 to 1 percent of the earth's atmosphere

- Carbon dioxide is a kind of greenhouse gas
- The earth 's atmosphere is made of 036 percent carbon dioxide by volume
- So, carbon dioxide is a greehouse gas accounting for 0036 percent of the earth's atmosphere

- Water vapor is a greenhouse gas accounting for 04 to 1 percent of the earth's atmosphere
- Carbon dioxide is a greehouse gas accounting for 0036 percent of the earth's atmosphere
- 04 is bigger than 0036
- So, water vapor is the largest amount of greenhouse gas in the atmosphere

Therefore, water vapor is the largest amount of greenhouse gas in the atmosphere
Question
Which gas accounts for the largest percentage of greenhouse gases in the atmosphere?

Context
- Carbon dioxide is a kind of greenhouse gas 
- The earth 's atmosphere is made of 04 to 1 percent water vapor by volume 
- 04 is bigger than 0036 
- The earth 's atmosphere is made of 036 percent carbon dioxide by volume 
- Water vapor is a kind of greenhouse gas