Final answer:
The skeletal evidence for speed, high levels of activity, and agility in dinosaurs is confined to coelurosaurs, theropods, and ornithopods. So, the correct answer is option d.
Step-by-step explanation:
The skeletal evidence for speed, high levels of activity, and agility in dinosaurs is confined to coelurosaurs, theropods, and ornithopods. These groups of dinosaurs have adaptations in their skeletal structure that allowed them to be swift and agile. For example, theropods like Tyrannosaurus rex had light, bird-like skeletons with air sacs and hollow bones that made them fast and agile hunters.
So, the correct answer is option d.