Parameter Tree:
EARTH SCIENCE > BIOSPHERE > ECOLOGICAL DYNAMICS > ECOSYSTEM FUNCTIONS > EXCRETION RATES

Definition:
Excretion is any of several processes by which excess water, excess or
harmful solutes, or waste materials leave the body by way of a urinary
system or certain glands.  


Reference:
Starr, C. and R.Taggart. 1998. Biology: the unity and diversity of life.
Wadsworth Publishing Company. Belmont, California.