Answer:
The pathway of oxygen from lungs to the body tissues is alveoli → red blood cells → blood vessels → tissues (option b).
Explanation:
The oxygen (O₂) required by the tissues comes from the air inspired by the respiratory system. The pathway of entry of O₂ to the body and tissues is:
Tissue oxygenation depends on the integrity of the respiratory and circulatory systems.
The other options do not show the correct order in which the oxygen travels from the alveoli to the tissues.