Question

Why is oxygen not transported by diffusion in large sized animal?

Answer 1

because diffusion is a very slow process.. so if we have diffusion like process then a single molecule of o2 takes more than 2 years

Answer 2

Diffusion is the movement of materials from a higher to a lower concentration. ... Oxygen concentration in cells is low (when leaving the lungs blood is 97% saturated with oxygen), so oxygen diffuses from the blood to the cells when it reaches the capillaries. Effectiveness of various oxygen carrying molecules.