Life's supporting gases are those gases with support life on Earth, There are multiple gases in the atmosphere some of them are required for the maintenance of life the most important gas is oxygen because it supports the most of the living species of the planet. They get infused with the oxygen carrier cells for example, RBC in human for making the cell structurally and functionally viable.
One more gas plays a major role in supporting life is Carbon dioxide because it is required in photosynthesis which ultimately makes food for the living species and maintains an equilibrium between them.