Class Trematoda: Infect the internal organs of hosts. Parasitic Can be endoparasites (live in the host) or ectoparasites (attach to external surfaces of the host. Size: ~ 1 cm to 10 cm Covered in an unciliated cuticle. Usually require 2 hosts to complete it's life cycle.
The difference between a mole and a wart is that moles are not contagious, but warts are. A mole, or nevus, is a collection of skin pigment cells. When they are small, they look like small brown dots. When the collection is larger, and slightly deeper, it can cause a raised skin colored bump over it.
They may also appear on other parts of the body. Warts have a rough texture and are caused by viruses, particularly one of several kinds of HPV (human papillomavirus). The virus causes keratin, which is a hard protein on the top layer of the skin, to grow too fast. Warts are not the same as moles.