You are given leech, Nereis, Scolopendra, prawn and scorpion and all have segmented body organisations. Will you classify them in one group? If no, give the important characters based on which you will separate these organisms into different groups.
All organisms given in the question do not belong to same group. Leech and Nereis belong to phylum annelida because they have metamerically segmented body, i.e., body is divided into many segments internally by septa. Body segments are lined up one after the other from head to tail. But Scolopendra, prawn and scorpion belong to phylum arthropoda as these have jointed legs and open circulatory system.