Question

Nematoblasts of Hydra are
A. Sensory
B. With nematocyst apparatus
C. Both A and B
D. None of the above

Answer 1

Hint: Hydra belongs to the phylum Cnidaria which is a genus of small, fresh-water organisms and also diploblastic. Hydra is native to temperate and tropical regions.

Complete answer:
Cnidaria is classified in the kingdom Animalia. They are mostly found in both marine and freshwater environments. Cnidaria involves a group of animals such as Corals, Sea anemones, jellyfish, hydra, etc. They have radial symmetry and follow both the mode of reproduction i.e. sexual and asexual. The term Cnidaria refers to the Cnidocytes which are specialized cells containing nematocysts which are stinging organelles that allow the Cnidaria to low their prey. The most common features of all Cnidarians are the Nematocysts or Cnidocytes.
Hydra being a diploblastic organism (i.e. their body derived from two embryonic cell layers which are ectoderm and endoderms but no mesoderm) that form the inner gastrodermis and the outer epidermis. This epidermis serves as a protective and sensory layer which is covered by a thin cuticle. It is composed of gland cells, interstitial cells, muscle cells, and cnidoblasts or Nematoblasts which are the special cells that act as stinging cells. Nematoblasts produce the nematocysts which are primarily used for capturing the prey, paralyzing prey, and also act as organs of offense but also for locomotion.

Hence, the correct answer is option (A).

Note: Stinging cells of cnidarians are present around the mouth area and tentacles (flexible, slender appendages present in an animal) and they tend to immobilize the prey with the toxins present in the cells.