Roundworms may be free-living or parasitic.
Dogs remain susceptible to reinfection with hookworms and roundworms.
Dogs remain susceptible to free-living or parasitic species.
Dogs remain what to free-living or parasitic species?
Options:
[A] hungry for
[B] warm-blooded
[C] susceptible
[D] fertile
[E] taken over by
[F] more abundant
[G] Animal survival
[H] friendly towards