The percentage of oxygen is due to the presence of plants and the process of photosynthesis, while the carbon dioxide is a product of animal respiration.
(The percentage of oxygen; is; due to the presence of plants and the process of photosynthesis) (the carbon dioxide; is; a product of animal respiration)
The percentage of oxygen the carbon dioxide
is is
due to the presence of plants and the process of photosynthesis
a product of animal respiration