The largest exchange of carbon in the carbon cycle occurs between the Earth's surface and the atmosphere, primarily through the processes of photosynthesis and respiration. These processes involve plants and other organisms taking up carbon dioxide from the atmosphere during photosynthesis and releasing carbon dioxide back into the atmosphere during respiration.

The fast carbon cycle involves relatively rapid exchanges of carbon between various reservoirs, including the atmosphere, the terrestrial biosphere (plants and soils), and the ocean.

Some of the major reservoirs and containers of carbon in the fast carbon cycle include:

The fast carbon cycle involves relatively short time scales compared to the slow carbon cycle, which involves exchanges of carbon over much longer time scales through processes like weathering and the formation of sedimentary rocks. Both fast and slow carbon cycles are essential for maintaining Earth's carbon balance and regulating climate.

Dr Gaurav H Tandon thank you for your contribution to the discussion

The ocean plays a critical role in carbon storage, as it holds about 50 times more carbon than the atmosphere. Two-way carbon exchange can occur quickly between the ocean's surface waters and the atmosphere, but carbon may be stored for centuries at the deepest ocean depths. Plants constantly exchange carbon with the atmosphere. Plants absorb carbon dioxide during photosynthesis and much of this carbon dioxide is then stored in roots, permafrost, grasslands, and forests. Plants and the soil then release carbon dioxide when they decay. The amount of carbon stored in a particular system is called a “stock” or a “pool”. The Earth's largest carbon stock is found within the continental crusts and upper mantle of the Earth, a large portion of which is sedimentary rock formed over millions of years. The biotic community includes all living organisms. This community may serve as an exchange pool and also serve to move chemicals from one stage of the cycle to another. The oceans are, by far, the largest reservoir of carbon, followed by geological reserves of fossil fuels, the terrestrial surface (plans and soil), and the atmosphere. Lithosphere (Earth's crust). This consists of fossil fuels and sedimentary rock deposits, such as limestone, dolomite, and chalk. This is far and away the largest carbon pool on earth. The largest reservoir of the Earth's carbon is located in the deep-ocean, with 37,000 billion tons of carbon stored, whereas approximately 65,500 billion tons are found in the globe. Carbon flows between each reservoir via the carbon cycle, which has slow and fast components.Carbon is stored in four major Earth reservoirs, including the atmosphere, lithosphere, biosphere, and hydrosphere. Each reservoir contains a variety of organic and inorganic carbon compounds ranging in amounts. The atmosphere is the reservoir of carbon that changes the most and the quickest with there being a lot of carbon coming in and going out.Carbon is in a constant state of movement from place to place. It is stored in what are known as reservoirs, and it moves between these reservoirs through a variety of processes, including photosynthesis, burning fossil fuels, and simply releasing breath from the lungs. The global carbon cycle and arrows indicate fluxes of carbon between the various reservoirs of the atmosphere, lithosphere, terrestrial biosphere, and the ocean. All stocks are expressed as 1015 g C. All fluxes are decadal means and expressed as 1015 g C y−1. Oceanic Reservoir is the correct option. Out of the entire amount of carbon in the world, over 71 percent is found dissolved in the oceans. Almost all of the remaining 71 percent is found in oceans.