<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}-->
Which of the following always involves the process of diffusion?
A. The gaseous exchange between the closely placed cells.
B. The movement of water into the cells of living organisms.
C. The movement of dissolved oxygen from the surrounding water into an amoeba.
D. The movement of carbon dioxide from the air into leaf cells.