The delicate balance of CO _ 2 and O _ 2 is NOT disturbed by

Plants use up carbon dioxide during photosynthesis and release oxygen into the atmosphere. This maintains the delicate balance between oxygen and carbon dioxide in the atmosphere.

The burning of fuels and cutting of trees is disturbing this balance in nature. As a result of such activities, the amount of carbon dioxide in the air is going up and the level of oxygen is coming down. Continuous and excessive use of fuels and deforestation would increase this imbalance. This is bringing about a warming of the atmosphere, called global warming. Respiration, is a natural process, So balance of ${CO}_{2}$ and ${O}_{2}$ not disturbed by respiration.