Question

Which of the following characteristics is mainly responsible for diversification of insects on land?
A. Exoskeleton
B. Eyes
C. Segmentation
D. Bilateral symmetry

Answer 1

Insects belong to the largest phylum of Animalia which is Arthropods. Arthropods include two-thirds of species. Arthropods come under invertebrates. Arthropods classify as millipedes, centipedes, crustaceans, insects, and arachnids.

Step by step answer: Insects come under the class of Hexapods. Hexapods mean six legs. Insects have three-parts of body head, thorax and abdomen, pair of antennae, and compound eyes. Insects are bilaterally symmetrical, segmented, trophoblastic, corporate animals. Insects have an endoskeleton. Ancient insects used to be aquatic organisms. Some of them evolved and adapted to live on the land and result in the diversification of insects on land. The most important adaptation is the exoskeleton. Insect exoskeleton is made up of chitinous which helps to prevent their skin from drying. Chitin helps to maintain the moisture of insects' skin. Some theory says that insects evolved from crustaceans.
Hence option A is correct. Exoskeleton characteristics are mainly responsible for the diversification of insects on land.

Additional Information:
Organism has two types of skeleton present in the body
Endoskeleton:
-Skeleton present inside the body.
-Mostly made up of bones.
-Amphibians, reptiles, mammals are some examples of endoskeleton animals.
Exoskeleton:
-Skeleton present outside the body.
-Made up a substance weaker than bone.
-Insects, crustaceans, shelled mollusks are some examples of exoskeleton animals.

Note: Most people consider that a spider is an insect but it is not true. Spider is not an insect because it has eight legs and its body is divided into two parts: head and abdomen. It comes under the class of arachnids meaning eight appendages.