Bisexual animals can use which mode of reproduction?

The bisexual animals possess the male as well as the female reproductive organs in the same body. The organisms can reproduce by various methods. The sperms from the male reproductive system can fertilize the female gamete in the same body by self-fertilization. In certain organisms, the self-fertilization is prevented because one of the reproductive systems develops before the other. In such animals, cross-fertilization is preferred in which the male gamete from one animal fertilizes the female gamete of the another. Parthenogenesis is the reproduction by the ovum without the process of fertilization. In certain lower organisms, parthenogenesis can be observed.