What is carbon dioxide used for?

Answer:

Plants "inhale" carbon dioxide and use the carbon to build their structures. They then release the oxygen into the atmosphere. The same is true with many plankton. Carbon dioxide is also frozen to produce "dry ice", and pumped into fire extinguishers to put out fires. Carbon dioxide is also forced into water, producing carbonic acid... that's the fizzy stuff that makes soft drinks bubble and makes you burp.

Answer:

Carbon dioxide is used in life jackets which often contain carbon dioxide for quick deflation. High concentrations can also be used to kill pests, such as the common moth ball. The gas is used commonly to produce carbonated soft drinks and soda water. Leavening agents produce carbon dioxide to cause dough to rise, it extinguishes flames and some fire extinguishes especially those designed for electrical fires, contain liquid carbon dioxide under pressure. Plants require it to conduct photosynthesis and green houses may enrich their atmospheres with additional CO₂ to boost plant growth.
The frozen form of carbon dioxide, dry ice, can be mixed with hot water to make a white gas that is used in theatres as steam