Respiration is a way to release carbon back into the atmosphere. removes carbon from the atmosphere.

the aanswer is photosyntheis that is because my friend said so XD

Latter reduces emission to the atmosphere but cannot reduce the amount of carbon dioxide already in the atmosphere which is also known as CDR  

The salivary glands produce saliva, which keeps the mouth and other parts of the digestive system moist. It also helps break down carbohydrates (with salivary amylase, formerly known as ptyalin) and lubricates the passage of food down from the oro-pharynx to the esophagus to the stomach.