Question

Transverse binary fission occurs in
A. Euglena
B. Amoeba
C. Hydra
D. Paramecium

Answer 1

Hint:Binary fission is an asexual method of reproduction. This mode of reproduction is used by members of archaea as bacteria. It results in cell division of parent cells to produce two viable cells. As prokaryotes have a simple structure so they can reproduce by binary fission.

Complete answer:
Option A: It is unicellular, flagellates having a mixotrophic mode of nutrition. Asexual reproduction is by longitudinal binary fission sexual reproduction is by longitudinal binary fission. Sexual reproduction is usually absent. Therefore, this is an incorrect option.

Option B: It is an aquatic protozoa protist which lives at the bottom of freshwater, pools, and stream, etc. They have contractile vacuole for osmoregulation and help to get rid of excess water. Asexual reproduction occurs by binary fission and multiple fission. Sexual reproduction has not been reported in Amoeba through irregular binary fission. Here, cytokinesis occurs along a plane that is perpendicular to the plane of karyokinesis. Therefore, this is an incorrect option.

Option C: It reproduces by both asexual and sexual reproduction. Hydra has a remarkable power of regeneration. Hydra reproduces by budding. Therefore, this is an incorrect option.

Option D: The most characteristic feature of a paramecium is the presence of a large number of cilia on the whole body. Cilia help in locomotion and to capture food. They reproduce asexually by transverse binary fission or budding and sexually by conjugation. Under unfavorable conditions, they form cysts. Paramecium shows nuclear dimorphism. Therefore, this is the correct option.

Thus, the correct answer is option (D) Paramecium.

Note: It is to be noted that when the micronucleus in paramecium divides through mitosis, the genetic material in the nucleus goes through four stages of mitosis i.e prophase, metaphase, anaphase, and telophase. During the micronucleus division, all energy is used for separation and duplication. Therefore, cell growth does not occur at this stage.