The Hadrosaurs are herbivores that had a long jaw with hundreds of grinding teeth at the end of thier jaw. Sown of them had large crests, and others had skin over their nose that could be inflated like a balloon. These dinosaurs appeared in the early Cretaceous period and died out at the end of the dinosaurs. They had short, powerful front legs that are only about half as long as the back legs. They could also rear up on only their back legs and run at a considerable speed of up to 30 mph on them to escape predators. If that doesn't work, then they use their long tail that takes up half of their body length and will hit their attacker with it like a baseball bat.
The Iguanadonts are a family similar to the Hadrosaurs but had a more primitive jaw more suited for the rough vegetation of the jurassic and not the more andvanced and easier to eat vegetation and flowering plants of the Cretaceous. They appered in the jurassic and lived through the Cretaceous. As an additional weapon besides their large tail and sheer size, they have a large claw on their thumb that when they rear up on their back legs, and be used like a spear and cause some serious damage.
The animal on the right is an Edmontosaurus, a hadrosaur, and the one on the left is an Ouranosaurus, an Igunanadont.