Characteristics of round and flat worms quiz online, multiple choice, 4th, 5th, 6th Grades. This is an online test in biology in which students learn about flat worms, their habitat, reproduction, digestive system and more. Also learn the differences that exist between flat and round worms based on thier characteristics. Also learn the classification of round and flat worms based on the kingdom and phylum. Further learn to classify different species of both worms - find examples of both species. This quiz will help parents and teachers as a free resource for preparing children before an exam.