There are blood vessels near the surface of the skin and when a frog is underwater, oxygen diffuses directly into the blood.

As the membrane of the air sacs is so thin, oxygen can easily diffuse in and out.

As the plaque begins to develop and expand, oxygen can no longer diffuse into the colonies.

It is perforated by a large number of fine breathing pores called lenticels through which oxygen diffuses.

Another disadvantage of a glovebox is that oxygen and water can diffuse through the plastic gloves.

Without a 'bubbler' or mixing, oxygen must diffuse from the surface of the water down to the depths of the tank, which is slow.

Elsewhere, at a similar structure known as the oval window, the bladder is in contact with blood and the oxygen can diffuse back.

The oxygen diffuses across the membrane to the cells in the cassette below.

The thin, external walls of the chimneys are porous and so oxygen from the outside atmosphere diffuses in.

Then the combustion will not start up again until enough methanol evaporates or oxygen diffuses back into the area around the platinum wire.