To which of the following classes does $Limulus$ belong?

The body of an insect is divisible into:

$A$ student has identified a triploblastic,coelomate,segmented animal as an arthropod. Which additional character should the student have verified before identifying that animal as an arthropod?

Which of the following is $NOT$ found as a respiratory organ in animals of the phylum $Arthropoda$?

An arthropod belonging to $Onychophora$ which possesses $nephridia$ is

Which of the following belongs to the class $Insecta$?