GREETINGS!
Diffusion is a process in which gases or liquid move from higher concentration to lower concentration
Osmosis is a process of movement of water molecules from higher concentration to the lower concentration through semi permeable membrane
SIMILLARITIES OF DIFFUSION AND OSMOSIS
Diffusion and osmosis both are the processes in which molecules move from high concentration to the lower concentration, also they do not require any energy so they both are passive transport examples.
The only dissimilarity is that in osmosis there is semipermeable membrane which Checks the movement of the water molecules ONLY
HOPE THIS HELPS YOU!