In fermentation, yeast ingests sugars and excretes ethanol. The liver preferentially excretes plant sterols over cholesterol. The fetus normally excretes AFP into its urine, hence into the amniotic fluid. In mammals, the skin excretes sweat through sweat glands throughout the body. Every adult human excretes between of phosphorus annually. It actively excretes salt out from the gills. The penguin excretes the salt byproduct as a brine through its bill. This gland excretes a high saline solution from their nose. Ten percent of the population in developing countries excretes oocysts. It excretes a concentrated brine from the nostrils. The infected human excretes the most oocysts during the first week. Each polyp excretes an exoskeleton near the base. The snail covers the hole with a mixture of the slime it excretes and dirt. It excretes a high saline solution from their nostrils. Black walnut is allelopathic, as it excretes chemicals into its environment that harm competition.