There are many causes of arthropods which make it , the largest group of animal kingdoms such as –

(i) Jointed legs that allow them to move and perform many other functions due to these jointed appendages.

(ii) Hardened skeleton made of chitin protects their body.

(iii) Hard skeletons reduce water loss from the body of organism

(iv) Demonstrate a different system for locomotion such as respiration and reproduction.

(v) Ability to live in diverse conditions and live in varied habitats.

(vi) Comparison to other phyla, they are pre-developed.

(vii) Well-developed sense organs and nervous system are present .

(vii) Some insects exhibit pheromones that enable communication to each others.