Question

Animals with metameric segmentation, bilateral symmetry and close circulatory system belong to the phylum_______.
a. Annelida
b. Echinodermata
c. Arthropoda
d. Mollusca

Answer 1

Phylum is a division which has the taxonomic category above class and below kingdom. According to biology, the term phylum was replaced by division. Here, based on the segmentation, symmetry and the circulatory system the animals which belong to some of the types of phylum can be found and analyzed.

Complete answer:
There are about 35 phyla in the animal kingdom. It can be classified based on the segmentation, symmetry and some of the differences. Firstly, in the phylum annelida there is a large phylum thereby having nearly 20,000 extant species with them. These kinds of phylum include ringed worms. These are mostly worm- like structures and they display bilateral symmetry with them. These have a closed circulatory system and metameric segmentation. Secondly, in the phylum echinodermata there is the body without the segmentation and this includes starfish and displays a radial symmetry. The shape of this phylum is flat and elongated. The common name for this phylum is echinoderm. Then coming to the phylum arthropoda, these are characterized by the jointed limbs and have cuticles with them. They are joint-legged animals. In the phylum mollusca, these also display in the bilateral symmetry and most have soft bodies with them. They are triploblastic in nature.

Hence, the correct answer is option (A).

Note: Annelids are found all over the world in all types of habitats. These are present mostly in the oceanic waters and fresh waters. In annelids the external morphological features are repeated in each body segment. The process known as metamerism involves here that allows animals to become bigger and make their movement more efficient.