Question

Bisexual animals can use which mode of reproduction?
A. Self-fertilization
B. Cross-fertilization
C. Parthenogenesis
D. All of the above

Answer 1

Hint: Bisexual organisms are those in which both male and female reproductive system are present in same individual. They are also known as hermaphrodites. Examples of bisexual organisms includes earthworm, leech, starfish, tapeworm etc. There are no separate sexes in many taxonomic groups of animals. Hermaphroditism is a normal condition that enables a form of sexual reproduction in which either one of the partners can act as female or male.

Complete answer:
Option A. Self-fertilization: The union of male and female gametes from the same haploid, diploid, or polyploid organism is known as self-fertilization or selfing. Self-fertilization is an extreme degree of inbreeding. Self-fertilization is common in many invertebrates.
Hence option A is correct.
Option B. Cross fertilization: The fusion of male and female gametes from different individuals of the same species is known as cross fertilization. It is also called Allogamy. Cross fertilization occurs in dioecious plants and in all animal species in which there are separate male and female individuals. It is a mode of reproduction in bisexual animals also.
Hence option B is also correct.
Option C. Parthenogenesis: Parthenogenesis is a natural form of asexual reproduction in which embryos grow and develop without being fertilized by sperm. It is the process of an embryo developing from an unfertilized egg cell. Parthenogenesis is also a mode of reproduction in bisexual animals.
Hence option C is also correct.
Option D. All of the above: Since options A, B and C are all correct.
Hence option D is the right answer.

Hence, Option D. All of the above is the correct answer.

Note:
Since a hermaphrodite can both give and receive gametes, being a hermaphrodite is thought to increase the chances of solitary organisms reproducing. This allows them to both share their DNA, and at the same time, they have the chance to develop an offspring of their own. Young which are developing in two different places decreases the chance of random events that will wipe out both young.