Dinosaurs are more closely related to reptiles than to amphibians. In fact, dinosaurs are classified as reptiles. Amphibians are lower on the evolutionary tree than reptiles. Reptiles developed from amphibians. Amphibians developed from fish.
A raptor was closely related to a bird because when the raptors or two legged herbivores were running away from predators then as they ran away they had to run up steeper things too get away and that is how they developed wings to help then get up steeper things.
Snakes and worms are not closely related. Worms are fairly primitive invertebrates, while snakes are vertebrates with backbones and ribs, a brain, and well-developed circulatory system, among other things. Physically, they are more closely related to birds than to worms.
No. Tuataras are more closely related to lizards and snakes than to dinosaurs. Dinosaurs are more closely related to crocodiles and even more closely related to birds, which are their only living descendants.
Both crocodiles and turtles are reptiles so they are related in that sense. However, among reptiles they are not very closely related. Crocodiles are more closely related to lizards and snakes than they are to turtles and, oddly, even more closely related to birds.