As we respire, we release co2. the carbon in this co2 is obtained from

From the food we eat

Explanation:

Carbon Dioxide is one of the most important greenhouse gas in the atmosphere. This CO₂ is released from the body of the living organisms during the process of respiration. This Carbon that is present in the CO₂ gas is obtained from the various types of food that the organisms eat. This carbon is taken into the body in the form of essential nutrients such as proteins, carbohydrates. When the oxygen reacts with the food inside the cells, it produces energy and in turn, gives out the CO₂ gas.

Thus, carbon is present in every living organism and plays a crucial role in the carbon cycle.

i think the answer is b.