What similarities are found among segmented worm, like the leech, and flatworms, such as the tapeworm? what differences are found among these two groups?

Well, both have no skeletal or exoskeletal system and steal nutrients from their hosts. A leech though, usually steals nutrients from latching onto a host and stealing nutrients and such through blood. A tapeworm is accidentally ingested and lives in the stomach of its host, stealing the nutrients from the food the host eats. Hope this helps!