free oxygen
- oxygenElement eight, colorless gas
- O2Molecular oxygen gas
- atmosphereGaseous layer around planets
- breathablePermits air passage
- airGaseous envelope surrounding Earth
respiration · photosynthesis · ozone · lungs · aerobic · oxidation · cyanobacteria · dissolved · molecules · breathe · life · combustion · reactive · gas · hemoglobin · cellular · mitochondria · aquatic
atmospheric presence
free oxygenanoxia
Absence of oxygen supply
oxygen depletion · anaerobic conditions · hypoxia · deoxygenated · vacuum