Final answer:
Water vapor is the most powerful greenhouse gas in terms of how heat is absorbed by one molecule of the gas.
Step-by-step explanation:
The most powerful greenhouse gas in terms of how heat is absorbed by one molecule of the gas is water vapor.
Water vapor has a high global warming potential (GWP) and is able to absorb a significant amount of infrared radiation.
While carbon dioxide, methane, and nitrous oxide are also greenhouse gases, water vapor is the most dominant in terms of its ability to absorb heat.