Answer: D. blood
The blood transports gases like carbon dioxide and oxygen to and from the heart and the lungs. It carries carbon dioxide, the waste or byproduct of cell respiration, to the lungs, which then oxygenates it. Oxygen is then transported via the blood to the heart, which helps to pump it to all organs of the body. Different nutrients are also transported by the blood. It serves as the transporter of minerals, vitamins, proteins, and carbohydrate to various organs for processing, which is used by the body.