Final answer:
The pelvic features associated with a dinosaur that has a toothless predentary and a beak are Ischium, Ilium, and Pubis. These are characteristic of ornithischian dinosaurs, while modern birds evolved from the saurischian lineage. Both theropod fossils and the anatomy of modern birds support the evolutionary link between dinosaurs and birds.
Step-by-step explanation:
The question is asking for the pelvic features associated with a dinosaur that possesses a toothless predentary and a beak. The correct pelvic features as parts of the hip bone are Ischium, Ilium, and Pubis. These belong to the pelvic structure of ornithischian dinosaurs, which are often referred to as "bird-hipped" dinosaurs, although modern birds evolved from the saurischian "lizard-hipped" dinosaurs. Specifically, the superior part of the hip bone is the ilium. Ornithischian dinosaurs have a pelvis that is constructed in a manner superficially similar to that of birds, but they are not the ancestors of modern birds; that distinction is reserved for certain theropods from the Saurischia clade.
Fossils like those of Archaeopteryx exhibit both dinosaur and avian features, such as feathers and a jaw with teeth, supporting the evolutionary link between dinosaurs and birds. Fossils of other theropods, such as Deinonychus, also show bird-like features including feathers, strong legs, and a mode of reproduction suggestive of endothermy.
Ultimately, birds are classified in the clade Neornithes, which encompasses all living birds and their most recent common ancestors among the maniraptoran theropods. Dinosaurs, including many theropods, had hollow bones and a respiratory system that is considered similar to that of birds, further highlighting their evolutionary connection.