Diffusion exchange between a membrane-bounded sphere and its surrounding.
D000818:Animals; D001001:Anura; D002463:Cell Membrane Permeability; D004058:Diffusion; D005260:Female; D005399:Fishes; D007700:Kinetics; D008433:Mathematics; D008566:Membranes; D010063:Ovum / Q000166:cytology / Q000378:metabolism; D011868:Radioisotopes; D011896:Rana temporaria; D014867:Water / Q000378:metabolism
D011868:Radioisotopes; D014867:Water