The figure given below is the characteristic structure of the phylum in which animals are aquatic, free swimming or sessile, mostly marine, radially symmetrical. Identify the phylum and correct function of the structure.
A. Ctenophora; Emission of light.
B. Porifera; Feeding, respiration and excretion.
C. Cnidarian; Anchorage, Defense and food capturing
D. Mollusca; Locomotion, transport of food and respiration.
Correct Answer : C.
The given figure shows the structure of cnidoblast. Cnidoblast is the characteristic feature of porifera phylum. A cnidoblast (also known as a cnidocytes or nematocyte) is an explosive cell containing one giant secretory organelle that defines the phylum Cnidaria (corals, sea anemones, hydrae, jellyfish, etc.). They are used for prey capture and defense from predators.