1 The kidneys are used to remove excess water and ions from the blood. 2  These are then expelled as urine. 3  The kidneys perform a vital role in homeostatic regulation in mammals, removing excess water, salt, and urea from the blood.
Ectoparasites Parasites that live on the outside of the host, either on the skin or the outgrowths of the skin, are called ectoparasites. They are directly transmitted between hosts.
To learn more about parasitism, review the accompanying lesson titled Parasitism: Examples & Definition. This lesson will help you: Define parasitism Compare and contrast endoparasites and ectoparasites Examine how parasitism is defended against