Question

The thallus of Volvox is called as-
A. Trichome
B. Coenobium
C. Coenocyte
D. Parenchymatous

Answer 1

Hint: Volvox is also known as globe algae. It is a polyphyletic genus of the green algae, belonging to the Volvocaceae family. They are present in spherical colonies constituting about 50,000 cellular structures. They live in freshwater.

Complete answer:
> Option A:
The trichomes are small hairy like outgrowth, which grows from the epidermis. The trichome length varies in some organisms, and is not a thallus. Thus, option [A] is incorrect.

> Option C:
The coenocytic is fungal bodies which have many nuclei that are enclosed in a single membrane. Thus, option [C] is incorrect.

> Option D:
The Parenchymatous are a type of cellular tissues which are soft, and could mainly be present in the pulp region of the pulp, apical regions, and others. These cells have a thinner cell wall, and they aid in multiplication of the cells. Thus, option [D] is incorrect.

> Option B:
When the arrangement and the number of cells are defined at the time of their origin and will remain constant throughout their lifespan, in their individual colonies, then each colony is known as coenobium. The Volvox forms colonies, so their cells are highly organized. The plant body is also termed as coenobium because it is largest and highly differentiated, and as a result would form the thallus. Therefore, it could be concluded that the thallus of Volvox is called coenobium.
Hence, the correct answer is option (B).

Note: Every mature colony of Volvox comprises a number of flagellated cells that are similar to Chlamydomonas. They are fifty thousand in number, approximately. They are present in hollow spaces, or the coenobium that consists of an extracellular matrix, which is made up of gelatinous glycoprotein.