Question

Bilateral symmetry, metameric segmentation, coelom, open circulatory system are the features of
A) Annelida
B) Arthropoda
C) Mollusca
D) Echinodermata

Answer 1

Hint:In 1969 R.H. Whittaker proposed the five kingdom classification where organisms were divided into kingdom Monera, Protista, Fungi, Plantae and Animalia. Within each kingdom the organisms were further divided into phyla based on their characteristics.

Complete answer
The organisms belonging to kingdom animalia were further divided on the basis of body symmetry, patterns of circulatory system, nature of coelom, body segmentation, notochord and arrangement of cells into germ layers. Annelida comprises the family of worms such as earthworms, leeches and ragworms. They are characterized by having bilateral symmetry, coelomate, with multiple body segmentation. Their circulatory system is closed in most species, where blood circulates within blood vessels.

Arthropoda comprises invertebrate organisms that possess exoskeleton and paired jointed appendages possessing bilateral symmetry and also a segmented body. They come in the form of haemocoel and an open circulatory system. Mollusca also consist of haemocoel and an open circulatory system along with a bilaterally symmetric and segmented body. Echinodermata comprises mostly marine animals that have radial body symmetry with coelom and an open and reduced circulatory system and their body is covered with cilia.

Hence the correct answer is option (B) Arthropoda.

Note:Apart from the above mentioned phyla of kingdom animalia it also consists of few others which include- Porifera, Cnidaria, Platyhelminthes, Nematoda and Chordata. Most of them share a few basic common characteristics but also comprises characteristics unique to each of the phyla.