Chapter 26, Problem 6A

Summary Introduction

Introduction :

Arthropods make up the largest phylum in the animal kingdom. They include insects, butterflies, moths, etc. They have segmented body and have an exoskeleton with jointed appendage. All these features help them to survive in all type of environments and habitats.

Answer to Problem 6A

Correct answer :

The correct answer is option (D) simple eye, compound eye, tympanum, thorax

Explanation of Solution

Explanation/justification for the correct answer :

Option (D) simple eye, compound eye, tympanum, thorax. Most arthropods have a pair of large compound eye that helps flying arthropods to see things in motion easily. Compound eyes help to detect colours, or movement of prey and predators. In addition, most of the arthropods also have 3-8 pairs of simple eyes that can detect light. The tympanum is a membrane that is used for hearing in arthropods. The thorax is the middle body region of the arthropod and not a sense organ. So, the correct answer is option (D).

Explanation for incorrect answer :

Option (A) exoskeleton, chitin, molting, growth. Most of the arthropods have an exoskeleton that helps protect the soft body parts, provide support and protect against water loss. It is made of a polysaccharide containing nitrogen bound with protein called chitin. As the exoskeleton is made of non living material, it needs to be shed by the arthropods in order to grow. This stage of shedding of the exoskeleton is known as molting. All these terms are related to the arthropod growth. So, this is an incorrect option.

Option (B) mandible, antennae, appendage, leg. The arthropods have paired appendages. The appendages are structures like legs, mandible and antennae that grow and extend from the body of the animal. The mandible, antennae and leg are related to appendages. So, this is an incorrect answer.

Option (C) cephalothorax, thorax, head, abdomen. The body of arthropods is mostly divided into three regions- head, thorax and abdomen. Some arthropods have a fused thorax and head known as cephalothorax. All these terms are related to body regions. So, this is an incorrect answer.