Answer: True
Explanation: Oxygen cycle is the process by which oxygen is released into the atmosphere by photosynthesis and is used by aerobic organisms while the carbon dioxide is released as a by product of respiration. This carbon dioxide is used in photosynthesis for production of glucose.
[tex]6CO_2+6H_2O\overset{sunlight}\rightarrow C_6H_{12}O_6+6O_2[/tex]
Hence, for oxygen to remain in the atmosphere, it has to circulate through various forms of nature and this circulation of oxygen is called as oxygen cycle.
