Both tapeworms and lice depend on a living host to survive. The relationship between the parasite, tapeworm or lice, isn't mutual. The parasite only benefits from the relationship, because the host provides them with plenty of nutrients. In some cases, tapeworms and lice can carry diseases and infect the host. So, there is your answer and goodluck!
They are parasites. parasites are organisms that live in or on an organism of another species. it benefits by deriving nutrients at the other's expense.
