Question

Which among the following is not the class of arthropoda?
A. Merostomata
B. Polychaeta
C. Chilopoda
D. Crustacea

Answer 1

A segmented invertebrate animal having paired jointed appendages and an exoskeleton is known as an arthropod. Insects, arachnids, myriapods, and crustaceans all belong to the phylum Arthropoda, which comprises arthropods.
The following features are listed below:
The body is triploblastic, segmented, and symmetrical on both sides.
They are organised at the organ system level.
The three components of the body are the head, thorax, and abdomen.
Their bodies are equipped with jointed appendages that aid in mobility.
Blood is present in the coelomic cavity.
They have a circulatory system that is open

Complete answer:
Option A: Merostomata are Phylum Arthropoda subphylum Chelicerata Merostomata Extant horseshoe crabs and extinct sea scorpions are among them.
So, option A is not correct.
Option B: Polychaete annelid worms are a type of annelid worm. Annelids are divided into three groups: Oligochaeta, Polychaeta, and Hirudinea. These species are mostly found in the sea. Fan worms, paddle worms, and sand worms are among them. Arthropods are divided into three groups: Merostomata, Chilopoda, and Crustacea.
So, option B is correct.
Option C: Centipedes are predatory arthropods that belong to the Chilopoda class of the Myriapoda subphylum, which also contains millipedes and other multi-legged organisms. Centipedes are metameric elongated organisms with one pair of legs per body segment.
So, option C is not correct.
Option D: Crustacean refers to any invertebrate animal belonging to the Crustacea subphylum (phylum Arthropoda). Among the most well-known crustaceans are crabs, lobsters, shrimp, and woodlice.
So, option D is not correct.

Note:
The kingdom Animalia contains the phylum Annelida, which is a fairly wide phylum. Annelids can be found in both aquatic and terrestrial habitats. These are invertebrate species that are bilaterally symmetrical. Their segmented bodies set them apart from other organisms.
Polychaeta
The body is separated into parts and is elongated.
They can only be found in the ocean.
True coelomates are worms that are bilaterally symmetrical.
Metanephridia and protonephridia are the mechanisms by which they excrete.
Fertilization is a process that occurs outside of the body.
Their neurological system is well-developed.
The circulatory system is one that is closed.