Answer:
The correct answer would be B. The respiratory system supplies the oxygen that the cardiovascular system transports to the different cells for the production of energy.
Respiratory system and cardiovascular system work together in order to provide oxygen to each cell of the body. They also help in removing the carbon dioxide (produced by cellular respiration) out of the body.
Respiratory system transport oxygen from outside the body to the alveolar site (in lungs). Oxygen is then carried in dissolved form with the help of hemoglobin (red blood cells) to all parts of the body.
Blood also carries deoxygenated blood (high carbon dioxide content) from all the cells to the alveolar site. The carbon dioxide is then excreted out of the body with the help of the respiratory system.
