Why do all living things give off carbon dioxide? Explain? Please :)
Swindler, one small tweak. Plants give off O2 as a bi-product of photosynthesis, but at night, with no sunlight to utilize, plants resort to using O2 and giving off the bi-product CO2. (Supposedly hospitals remove plants from ICU units because of this.) And I think that some of the really exotic bacteria also give off other bi-products, but they are very rare.
Like Swindler said, CO2 is produced by cellular respiration in what is called the Krebs cycle. It has something to do with ATP molecules, but it has been 40 years since I studied this stuff, so that's all I remember.
Hope this helped some.
Plants also consume oxygen and give off CO2 because they need energy to live too. The leaves also take in CO2 and give off oxygen as they make the food for energy. But the roots don't!
All oxygen breathing creatures use the oxygen (O2) to burn molecules that contain carbon (C). But some creatures live without air, and give off other products like alcohol instead.
Not all living things give off carbon dioxide. No plants give off CO2, and often sea creatures don't.
It's all due to cellular respiration. Take on Oxygen and sugar, convert that to energy, and expel the waste: carbon dioxide.