Question

What are the reasons that you can think of for the arthropods to constitute the largest group of the animal kingdom?

Answer 1

Hint: With about nine lakh species, Arthropoda is the largest phylum. They might be aquatic, terrestrial, or parasitic in nature. Their exoskeletons are chitinous, and their appendages are jointed.
This phylum has numerous substantial classes, including Insects, which constitutes a significant fraction of the world's animal species. They have the potential to thrive in any environment.

Complete answer:
Arthropods' amazing diversity and success can be attributed to their very adaptive body plans. Arthropods have evolved a variety of appendages, including antennae, claws, wings, and mouthparts, allowing them to fill practically every niche and habitat on the planet.
Around 80% of all species in the animal realm belong to the phylum Arthropoda. The following are the reasons why arthropods are the most numerous:
On land, joint legs provide additional mobility.
The body is protected by a hard exoskeleton composed of chitin.
The strong exoskeleton decreases body water loss, making them better suited to terrestrial settings.
Internal fertilization protects the progeny from harsh external circumstances.

Additional information:
Characteristics-
The body is triploblastic, segmented, and symmetrical on both sides.
At the organ system level, they are organised.
The three components of the body are the head, thorax, and abdomen.
Blood is present in the coelomic cavity.
They have a well-functioning circulatory system.
A pair of compound eyes can be found on the head.

Note:
Endoskeleton and Exoskeleton are body sections of living creatures that have a complex network of organs.
An endoskeleton is a hard element that serves as the structure's internal support. It's termed a living structure because it's made of endoderm. Cartilage, bone, and other endoskeleton components are examples.The exoskeleton is the hard outside component of the body that protects the soft tissues and muscles. It is made up of ectoderm and is classified as a non-living structure. Hair, feathers, scales, horns, and other exoskeleton components include hair, feathers, scales, and horns.