Final answer:
The component of internal respiration is C: Diffusion of carbon dioxide from tissues to blood, which is part of the gas exchange process at the tissue level.
Step-by-step explanation:
The component of internal respiration in the given options is C: Diffusion of carbon dioxide from tissues to blood. Internal respiration is the gas exchange that occurs at the level of body tissues, where oxygen is delivered to the cells and carbon dioxide, a waste product, is taken from the cells to be transported back to the lungs. This process involves oxygen dissociating from hemoglobin within red blood cells due to the lower partial pressure of oxygen in the tissues and the higher partial pressure of carbon dioxide in the tissues compared to the blood. As a result, carbon dioxide diffuses into the blood to be carried away. Diffusion of oxygen from blood to tissues is also considered a component of internal respiration, as it is the counterpart process where oxygen is supplied to the cells.