Question

____________is the largest cnidoblast.
A. Atrichous isorhiza
B. Holotrichous isorhiza
C. Desmonema
D. Stenotele

Answer 1

Hint: This is a pear shaped structure and occupies the entire space of the cnidoblast in which it lies.

Complete answer:
Cnidoblast is an explosive cell containing one giant secretory organelle called a cnidocyst (also known as a cnida or nematocyst) that can deliver a sting to other organisms. Cnidae are used to capture prey and as a defense against predators. Cnidoblast is also known as cnidocyte or nematocysts commonly known as dinoflagellate. It is distinct from the similar subcellular structures found in the cnidocyte cells of cnidarians, a group of multicellular organisms including jellyfish and corals; such structures are also often called nematocysts.
The stenotele is the largest and most complex nematocyst / cnidoblast. It occupies the entire space of the cnidoblast in which it lies.

Additional information:
> Atrichous isorhiza is a type of nematocyst present on the tentacles and helps Hydra to locomote also known as inchmovement or somersaulting.
> Holotrichous isorhizas are oval or cylindrical in shape. The thread tube is Hulong with a narrow butt and forms three of four transverse coils. It bears a spiral row of small spines and may coil upon discharge.
> Desmonema is a genus of jellyfishes in the family Cyaneidae. Has a ring shaped zone of tentacles.

So, the correct answer is stenotele.

Note: Stenotele (noun; Greek stenos, narrow; telos, the end): (Cnidaria) A stinging nematocyst; a spirally coiled thread armed with spiral rows of projections that is provided at its distal end with a lid (operculum); a penetrant.