Question

Arthropoda is differentiated from annelids by
A. Segmented body
B. Absence of nephridia
C. Eyes
D. None of the above

Answer 1

Hint: Annelids and arthropods both have segmented bodies. Annelids excrete through nephridia while in arthropoda excretion occurs through malpighian tubules. Arthropods have compound eyes and annelids have ocelli that function as eyes and detect the direction.

Complete answer:
Arthropods have jointed feet that have exoskeleton, a segmented body and paired jointed appendages. They include insects, arachnids, myriapods, and crustaceans. They have jointed limbs and cuticle made of chitin. Chitin has calcium carbonate in it. Their body plan consists of segments, with the pair of appendages. They have an internal body cavity known as Haemocoel. Body of Arthropods is divided into head, thorax and abdomen. They have an open circulatory system. Locomotion is done by the jointed
appendages and/or wings. Excretion in the arthropods occurs by the malpighian tubules.
Annelids have external division of the body. They show the presence of a closed circulatory system. Locomotion in the annelids occurs by the chaetae or parapodia. Excretion in the annelids occurs through nephridia. Some of the annelids have ocelli type structure in their body. It function as eyes that detect the direction from which lights are coming. Arthropods have compound eyes that form apposition images.From the above information we can say that arthropoda is differentiated from annelids by absence of nephridia.

So, the correct answer is option B.

Note: Arthropods and annelids have many similar features. They both are segmented, and have a pair of appendages on each segment. The nervous system in arthropods is similar to the annelids. They both have tubular, dorsal hearts, which can be modified later. In arthropods coelom is present only in the embryo. Other features which can be used to distinguish between arthropods and annelids include location of the gonopores, structure of the head, and adaptations of the respiratory and excretory systems.