Question

Which of the following employs sexual reproduction?
A. Amoeba
B. Euglena
C. Plasmodium
D. Sycon

Answer 1

Hint: The production of young ones or offspring from organisms similar to themselves is referred to as reproduction. Reproduction can be sexual or asexual. Asexual reproduction can take place by fission, budding, fragmentation, gemmae, regeneration, spore formation, and vegetative propagation.

Complete answer:
Reproduction in Amoeba can take place either by simple binary fission or multiple fission. Longitudinal binary fission is the mode of reproduction in flagellates like Euglena. In this type of reproduction, the plane of division passes along the longitudinal axis of the body. The Plasmodium undergoes multiple fission. Sycon belongs to the Phylum Porifera. It can reproduce either by sexual reproduction or asexual reproduction. In the case of asexual reproduction, Sycon undergoes exogenous or external budding. Here, a bud grows on the outer surface of the body. The bud remains attached and forms a colony. Another type of asexual mode of reproduction in Sycon is regeneration. Sycon is a hermaphrodite. Hermaphrodite is a type of organism where both male and female sex cells are present in the same animal. In the case of sexual reproduction in Sycon, the archaeocytes produce both the sperm and the ova. The archaeocytes are present in the mesoglea. Thus, the sperm enters the body of a sponge along with the incurrent water and unites with the ovum to form the zygote. The zygote undergoes holoblastic unequal cleavage.
Thus, the correct option is D-Sycon.

Note: Some important points are listed below:
a. Sycon being a multicellular organism is capable of both sexual and asexual reproduction.
b. The sexual mode of reproduction in Sycon is internal.