GENERAL HISTOLOGY

Detailed explanation-1: -The valves that form the head can open and close and the primary function of the pedicellariae is to keep the surface of the test free of debris and small parasites.

Detailed explanation-2: -Pedicellariae are minute grasping organs found only in sea urchins and starfishes of the phylum Echinodermata. The pedicellariae are basically made of calcareous ossicles and in most cases operate either like a pair of scissors or a pair of forceps.

Detailed explanation-3: -Echinoderms as Medicine For example, some sea cucumber toxins slow down the growth rate of tumor cells, so there is an interest in using these in cancer research. Sea urchins are also model organisms used in developmental biology research.

Detailed explanation-4: -The sea star belongs to the phylum Echinodermata and the class Asteroidea. Therefore, the presence of pedicellariae is the characteristic feature of Asteroidea. Thus, the correct answer is option B. i.e., Asteroidea.