Greenhouse gases are called as such because they -
A greenhouse gas (sometimes abbreted GHG) is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect. The primary greenhouse gases in Eah's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide and ozone. Without greenhouse gases, the average temperature of Eah's surface would be about -18 degC (0 degF), rather than the present average of 15 degC (59 degF). The atmospheres of Venus, Mars and Titan also contain greenhouse gases. Ref : https://en.m.wikipedia.org/wiki/Greenhouse_gas
Are used in warming plant growth chambers
Help inmaintaining atmosphereic O2 and CO2 balance
Ar produced by green photosynthesizing plants and are trapped in the eah's atmosphere
Prevent the escape of heat waves reradiated from the eah's surface
Environment and health