Plants use photosynthesis to turn carbon dioxide and water into sugars and oxygen. The reverse process is respiration, which takes the sugar and oxygen are releases carbon dioxide. Both plants and animals use respiration to tap into the energy stored in the sugars.
When plants use photosynthesis, they absorb carbon dioxide. When they use respiration, they release it. You get the formula for respiration by reversing the arrow in @Sanger‘s equation and replace light with energy.
To add to what @LostInParadise wrote plants only use more CO2 than they release when they are actively growing. A mature plant/tree is almost perfectly carbon neutral.
Yes, but it is a good idea to understand that when you stare at all those living trees and plants, you are looking at sequestered carbon and we could stand to snatch a lot more of it from our air and oceans.
@stanleybmanly true but then you should chop those trees down, turn them into something useful that your won’t burn (like books) and plant new trees so they can take more CO2 out of the atmosphere.
Or alternatively stop polluting the ocean and killing all the phytoplankton that are doing all the actual heavy lifting in turning co2 into oxygen.