Which of the following is not a major contributor to global warming?
water vapor
sulfur dioxide
nitrous oxide
methane

Water Vapor

Explanation:

Water vapor, sulfur dioxide, nitrous oxide and methane are the examples of greenhouse gases. Except water vapor all other gases are responsible for the  global warming. These gases have a diatomic structure which is responsible for the absorption of the heat energy from sunlight. This results in increase in the temperature of the atmosphere hence, will result in global warming. Water vapors will be blown high up in the atmosphere the accumulated water vapors when condense will result in the precipitation in the form of rain, therefore will cool the atmosphere instead of warming it like other gases.