Question

What is the distinguishing feature between an insect and a crustacean?
A. Number of appendages
B. Number of eyes
C. Presence of wings
D. Arrangement of nerve cells

Answer 1

Hint: To provide an answer to this question we should know about the various classes of the arthropods. Arthropoda is known to possess the jointed appendages. In addition, the arthropods are classified based on the appendages and the body parts.

Complete answer: The most distinguishing feature between an insect and a crustacean is the number of appendages. Insects and crustaceans can be differentiated or distinguished based on the number of appendages. The insects have three thoracic segments. Each pair of legs that arise from each thoracic segment. On the other hand, crustaceans have 4+2 pairs of legs. The 4 pairs of legs arise from their body and two pairs from the head.
a) Number of eyes: Insects and crustaceans have the same number of eyes. Insects have one pair of simple eyes and one pair of compound eyes. Similarly, crustaceans also have one pair of simple eyes and one pair of compound eyes.
b) Presence of wings: Insects usually have two pairs of wings. However, some insects even have one pair of underdeveloped wings or no wings. On the other hand, crustaceans have no wings at all.
c) Arrangement of nerve cells: Insects and crustaceans both have a ladder-like nervous system, which is the feature of the phylum Arthropoda. Their nervous system consists of a brain ring and several nerve cords connected to it.
Hence, the correct answer is option A.

Note: Apterygota is a subclass of the class Insecta. It consists of all the insects that have no wings. The members of this class include small and agile insects. It is believed that some of these never possessed wings and others lost them during evolution. Examples of wingless insects are Silverfish.