Question

Stinging cells or cnidoblasts are the characteristics of
(a) Coelenterata
(b) Annelida
(c) Echinodermata
(d) Platyhelminthes

Answer 1

Hint: They are the characteristics of an animal phyla Cnidaria. Cnidaria includes coral animals, sea anemones, true jellies, sea pens, and Ctenophora (comb jellies) . They do not have a specialized circulatory system and will undergo diffusion across the tissue layers.

Complete answer:
Those animals having stinging cells or cnidoblasts on their tentacles or various parts of their body belongs to the phylum Coelenterata. These stinging cellhelps the organism in anchorage, defense, and prey capture. Therefore, they are also known as cnidarians.
Characteristics
The coelenterates are all aquatic and mostly are marine animals. Their body is radially symmetrical, diploblastic, and does not possess coelom. The hypostome (a mouth part) is the opening part of the body that is surrounded by various sensory tentacles constituting either nematocysts/colloblasts that help them in capturing their planktonic prey. These tentacles are surrounded by a cavity known as the gastrovascular cavity or coelenteron. The mother-cells of the nematocysts are called cnidoblasts. Each cnidoblasts cell will produce one nematocyst. The nematocysts are packed in gland cells, sense cells, and cnidoblasts.
Both intracellular and extracellular digestion can occur. Respiration and as well as the excretion are accomplished by simple diffusion. A network of nerves is spread throughout the body. These animals will reproduce asexually via budding. However, sexual reproduction can occur in some groups.
So, the correct answer is ‘Coelenterata’.

Note: The evidence of Coelenterata is found 7 million years ago and reports state that it originated even before the fishes. Additionally, it might be the first animal tissue that has a tissue-level organization. The word coelenterata was derived from the two ancient Greek words Koilos, meaning hollow, and enteron, meaning intestine.