Question

Discharged nematoblasts are replaced by new ones formed from
(a) Nematoblast initials
(b) Interstitial cells
(c) Amoebocytes
(d) Archaeocytes

Answer 1

Hint: It is cell organelles found in specialized cells called cnidocytes or cnidoblasts, which are modified epidermal interstitial cells. A Cnidoblast is an oval or rounded cell with a conspicuous nucleus lying on the basal side. In hypnotoxin, An oval or pyriform sac or bladder is present inside the cnidoblast that is filled with a toxin, which is a blend of proteins and phenols.

Complete step by step answer:
A nematocyst isn't a cell since it is chitinous and non-living. A reasonable space that emerges in the cnidoblast, space will develop and the cell secretes a twofold walled chitinous capsule that has a cover or operculum. Nematocysts are particular stinging cells explicit to Coelenterates that go about as organs of offense and safeguard. They are likewise known as Cnidae and consequently, and the coelenterates are additionally known as Cnidarians. The cells that produce nematocysts are called nematoblasts.

So, the correct answer is ‘Nematoblast initials’.

Additional information:
TYPES OF NEMATOCYSTS
There are 30 different types of nematocysts found in various groups of cnidarians.
Penetrants: It is of two kinds, stenotele found in Hydra and euryteles found in jellyfishes. They are the biggest (16 microns in diameter) and most complex nematocysts. Basically, it is pear-shaped and its thread tube is long and hollow, coiled transitionally, and bearing three huge stylets and three rows of little spines at its heavy base.
Volvents: The small, pear-shaped nematocysts around 9 microns long are called the solvents or desmosomes that consist of a short, thick, smooth, spineless, and elastic thread tube that is closed at the apical end.
Spirocysts: Generally, it is found in sea anemones in which the threaded tube is spirally coiled around the capsule in the resting stage.
Ptychocysts: It is also found in anthozoans. The thread tube bears fine tubules that form an adhesive net on release.
Glutinants: It secretes a sticky substance that helps in affixing the tentacles to solid objects and thus helps in movement and food capture. They likewise inject hypnotoxin. They lack a butt and their thread tube is of the same diameter throughout.
Stereoline glutinant: They are short oval or extended glutinants likewise called atrichousisorhizas because they do not possess spines and butt.
Streptoline glutinants: It is also called Holotrichous isorhiza, they are oval or cylindrical in shape and the threaded tube is long with a narrow butt. The string tube is pointed and opens at the tip and bears a spiral row of little spines.

Note: Nematocysts may occur scattered throughout the body surface, except the basal disc. They are abundant in the tentacles and hypostomes. On tentacles, they form a “battery of nematocysts'' which are used for paralyzing the prey. A battery comprises a couple of enormous central nematocysts encompassed by 10-12 little ones.