Higher organisms use a transport system and not diffusion only to distribute nutrients because
-
A.
the ratio of their surface area to volume is small -
B.
metabolic waste products diffuse to the surface of the organisms -
C.
the rate at which nutrients and other substances diffuse increases -
D.
substances to be transported move shorter distances to reach the numerous cells -
E.
the internal structures of the organisms are in direct contact with the environment.