Which of the following descriptions of the susceptible animals are right ( )

A、Susceptible animals include the animals that are susceptible to certain kinds of parasites because of lacking immunity;

B、Susceptible animals include the animals that are susceptible to certain kinds of parasites because of their low immunity;

C、Different breeds of animals appear to have different levels of susceptibility to the same parasite species. ;

D、Every animal species is only susceptible to certain kinds of parasite species.