Animals create carbon dioxide when the oxygen combines with food in the cells of the animals to produce energy for daily activity and then the animals gives off carbon.
Then the carbon combines with the oxygen to form carbon dioxide (CO2) which then is released back into the atmosphere as a waste product when animals breathe and exhale.
Carbon Dioxide is produced by almost all living organisms (both plant and animal). It is given off, (exhaled) into the air every time we breathe.
Even organisms without lungs or gills release carbon dioxide into the environment.
This includes insects, plants, bacteria, etc.
Organisms play an important role in the carbon cycle in the following ways.
Animals obtain their carbon by eating plants; they release carbon in respiration.
Micrororganisms (such as fungi and bacteria) return carbon to the environment when they decompose dead plants and animals.
There are natural sources of atmospheric carbon dioxide, such as outgassing from the ocean, decomposing vegetation and other biomass, venting volcanoes, naturally occurring wildfires, and even belches from ruminant animals.
In animals, oxygen combines with food in the cells to produce energy for daily activity and then gives off carbon.
The carbon combines with oxygen to form carbon dioxide (CO2) and is released back into the atmosphere as a waste product when animals breathe and exhale.