Question

Which one feature is common to leech, cockroach, and scorpion?
A.Nephridia
B.Ventral nerve cord
C.Cephalization
D.Antennae

Answer 1

Hint: Limbs allow animals to rapidly navigate complex terrain, groom, manipulate objects, and communicate. In invertebrates, neural circuits in the spinal cord coordinate the actions of each arm or leg. Thoracic circuits perform comparable tasks in insects. The thoracic segments of the fruit fly, Drosophila melanogaster, house the ventral nerve cord (VNC) which is a fusion of three thoracic and eight abdominal ganglia.

Complete answer: Nephridia- It is the unit of excretory system in many of the primitive invertebrates and also in some amphioxus; It expels the waste material from the body to the exterior. The evolution of Nephridia made the tissue specialized and eliminated the need for all cells of an organism to be in contact with seawater which helps in the diffusion of metabolic wastes.
Ventral nerve cord- This is the major structure of the invertebrate central nervous system. It is functional as the vertebrate spinal cord. The ventral nerve cord coordinates signaling from the brain to the body.
Cephalization- It is an evolutionary trend in which over many generations, sense organs, the mouth, and the nerve ganglia have become concentrated at the front end of an animal which produces a head region.
Antennae- This is present in the arthropods' heads which are connected to the first one or two segments. They vary in size and structure but they are always made up of one or more jointed segments. They are typically sensory organs.
Hence the answer is option B, Ventral nerve cord.

Note: Nephridia are the excretory organs in annelids like in earthworms and leeches. Arthropods like cockroaches and scorpions consist of a head, abdomen, and thorax. Cephalization is the property of the head formation. Antennae are found in arthropods and are absent in annelids like in leech. Annelids and arthropods have a ventral nerve cord and they run ventrally below the gut and connect to the central ganglia.