Amargasaurus.
Argentinosaurus was the biggest hervivorous dinosaur that has a long neck.
The scientific name of a long neck dinosaur is Brachiosaurus.
grass and leaves
Diplodocus.
A long neck dinosaur that eats plants
Plesiosaur
This depends on which long-necked dinosaur you are talking about. Heights varied between species.
Janenschia is a dinosaur. It was a huge dinosaur with a long neck and tail.
mamenchasaurus
it has a long neck
One particular Dinosaur called Hadrosaurs (Duck-billed dinosaur)
The small dinosaur with the frill around its neck is called a Triceratops.