Photosynthesis is a process by which plants use sunlight, water, and carbon dioxide to produce carbohydrates, and other biological compounds, which reduces the amount of carbon dioxide in the air. This is the difference between plants and animals. The carbon dioxide is stored in the plants until they decompose or are burned. So, for example, each fall when the trees lose their leaves and the plants die the level of carbon in the atmosphere goes up. The rest of the tree, bark etc., does not continue to absorb carbon. Plants only take in carbon so long as they are growing and not after they have reached their natural height. Planting trees and other plants is one component of the solution to global warming, but the number of plants we have now cannot consume more carbon than they already do, and there is some evidence that warmer temperatures make photosynthesis more difficult.
The answer is RESPIRATION