Question

Largest unicellular organism is
A. Yeast B. Acetabularia C. planaria D. volvox.

Answer 1

Hint: Alga is the largest single celled organism. Some of the green algae range from 6 inches to 12 inches in length and the name of the algae is Caulerpa taxifolia, it is aquatic in nature and its largest single cell is the ostrich egg.

Complete answer:
Acetabularia is the largest unicellular green algae which is belong to polyphysaceae family and usually found in subtropical water. It reaches to the size .5 to 10 cm in length. It is gigantic is size and excellent for the study of cell biology.
A. Yeast :- it is the single celled organism which represents the fungus, its scientific name is saccharomyces cerevisiae. It is used in food processing and for the fermentation for the formation of beer like beverages products. Numerous yeast are available for different purposes.
 C. Planaria:- It is one the kind of multicellular flatworm free living and belongs to Platyhelminthes phylum. They are found in aquatic regions, fresh and marine too, or sometimes in humid regions. It possesses some extraordinary ability to regenerate itself and reproduce asexually by binary fission.
D. Volvox:- It is a kind of unicellular green algae which belongs to the family volvocaceae, it forms spherical colonies upto 50,000 cells, it is usually found in damp places or aquatic habitat. They show both kind of reproduction like sexual and asexual reproduction, which is depends on environmental conditions. As they live in colonies, their size is also small as compared to acetabularia algae.

So, the correct answer is option B.

Note: Volvox and acetabularia both are green algae and belong to different families. Volvox lived in colonies and small in size that’s why it formed colonies while acetabularia so large it may live in groups but number is less as compared to volvox.