Question

Which one of the following is a matching pair of a body feature and the animal possessing it?
A. Ventral central nervous system - Leech
B. Pharyngeal gill slits absent in embryo - Chameleon
C. Ventral heart - Scorpion
D. Post-anal tail - Octopus

Answer 1

The leech nervous system consists of a ventral nerve cord composed of cephalic ganglia and segmental ganglia. They have a conspicuous ganglion at the caudal end of the nerve cord.

Complete answer:
The world is a home for many species. Different species have different body structures and mechanisms. Depending upon their body structure, mechanism, cell, etc. every living being can be classified.
Leech is a semi-aquatic annelid worm. The nervous system of leech consists of a ventral nerve cord consisting of cephalic ganglia and segmental ganglia. In addition, the leeches have a conspicuous ganglion at the caudal end of the nerve cord, the main role of which is believed to be the regulation of the rear sucker. Leech has a ventral central nervous system.
Pharyngeal gill slits and post-anal tails are typical characteristics of chords. Chameleon is a chordate, because it has pharyngeal gill slits in the embryonic stage. Pharyngeal gill slits are evident in the Chameleon embryo.
Mesosoma includes the heart or "dorsal vessel" which is the nucleus of the scorpion's open circulatory system. The heart is continuous with a deep arterial structure that extends around the body. The heart of the scorpion is present in the mid-dorsal area and not in the ventral area.
Many of the chords have a post-anal tail. The post-anal tail is an extension of the body that extends beyond the end of the anal. In certain animals, such as humans, this characteristic is present only during the embryonic development. Octopus is a mollusks and it has no post-anal tail.

Thus, the correct answer is option A. i.e., Ventral central nervous system - Leech.

Note: Leeches are segmented parasitic or predatory worms that belong to the Annelida phylum and form the Hirudinea subclass. They are clearly linked to oligochaetes that include earthworm, and, like them leeches have soft, segmented, muscular bodies that can contract and lengthen.