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

Explanation

The phylum, Arthropoda, consists of more than two-thirds of the animal species on earth. The reasons for the success of arthropods are as follows.
`implies` Jointed legs that allow more mobility on land
`implies` Hard exoskeleton made of chitin that protects the body `implies` The hard exoskeleton also reduces water loss from the body of arthropods making them more adapted to terrestrial conditions.