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.
Warts are generally caused by a human virus known as papilloma while moles are generally related with age and caused by hormones and environmental factors. There are cases when kids are born with moles but in general moles on the face increase with increase in age.
@StarJo-- I think another difference between them is that moles have a lot more melanin than skin tags and are also affected by the sun a lot more. Skin tags don't look any different than the rest of my skin but moles are always dark brown, almost-blackish.