They can be used to produce vaccines.
They can be used to determine the response of tissue to drugs.
They can be used to produce hormones.
Answer:
Reproduction; but only in a host cell
I'm thinking true heres why lets say you have a bird and the bird eats worms.. and all the worms in the world are gone the bird will die and what ever animal ate that bird will die and what ever animal ate that bird will die and so on
my guess
