about surface area and volume.
Large organisms have a small surface area to volume
Some organisms have a body shape adapted to
increase their surface area e.g. flatworms.
Some large, active organisms have specially adapted
surfaces for gas exchange e.g. lungs and gills.
The mesophyll cells of flowering plants provide a
large respiratory surface.
Some large, active organisms use ventilation
mechanisms to ensure a constant concentration gradient.
Organisms use transport systems to bring substances
to cells by mass flow.