* Diffusion is a slow process: It relies on the random movement of molecules and is heavily influenced by distance. As an organism grows, the distance between cells increases, making diffusion less effective.
* Surface area to volume ratio: As organisms grow, their volume increases faster than their surface area. This means there is less surface area available for diffusion to occur, further hindering nutrient transport.
* Specialized systems: To overcome the limitations of diffusion, larger organisms have evolved specialized systems like circulatory systems (blood vessels and heart) to transport nutrients throughout their bodies.
Therefore, diffusion of nutrients doesn't completely stop, but its role becomes less significant in larger organisms. Specialized systems take over the primary role of nutrient transport.
