The correct option is C Alveoli
∙ Alveoli are balloon-like structures present in lungs. They provide a large surface area for exchange of gases. Their walls have an extensive network of blood vessels.
∙ Arteries carry oxygenated blood from the heart to all parts of the body.
∙ Air passes through the pharynx into the wind pipe. Both food pipe and wind pipe originate here. It is commonly referred as throat.
∙ Capillaries are the smallest blood vessels in our body where nutrient and waste exchange between blood and tissues takes place.