The biggest dinosaur is probably ultrasauros. We only have a few bones of this late Jurassic (140 million years ago) plant-eater from Colorado, but the bones show an animal who was six-stories high and may have weighed more than 50 tons. A four-legged plant-eating dinosaur found recently in Argentina, argentinasaurus, may have been even heavier than ultrasauros. If it was a brachiosaur like ultrauros then it probably was the biggest, but if it was a titanosaur, another kind of big plant-eater common in South America, it wouldn't have been so bulky.
argentinasaurus was the biggest of all dinosaurs and a plant eater they are know as herbivores
Edit: It depends on what you mean by ''largest''. Usually that means the most massive or heaviest. The biggest group of herbivorous dinosaurs where the sauropods (the ''long necks'').
Every dinosaur weight or mass you have ever heard is an estimate. Estimates are difficult when you only have the bones because of the uncertainties of unknown soft tissue. Also the largest known dinosaurs arrn't very complete which makes estimating even harder. In short there is no straight answer.
Take Brachiosaurus brancai (some call it Giraffatitan brancai ). It has been estimated as low as 15 tons and as high as 80 tons using different estimates.
Those two estimates are extreme and are generally thought to be wrong. Most estimates these days put it in the 25-30 ton range.
Argentinosaurus is undoubtingly a massive animal but it isn't fully known. There are a lot of uncertainties as to its exact proportions. Estimates have ranged from 60 -100 tons.
There are other, even less complete giant dinosaurs which 'might' be bigger.
Here are some other potential candidates to look into:
Amphicoelias, Futalognkosaurus, Puertasaurus, Paralititan, Antarctosaurus, Sauroposeidon, Turiasaurus
There are also some giant hadrosaurs (duck bill dinosaurs) that grew very large. But none are as large as sauropods.
The most tallest and strongest plant eating dinosaur was the Argentinosaurus. It was believed to be the largest land animal which had ever lived.
The biggest were the plant-eating Sauropoda.
It is a plant eating dinosaur
It is a plant eating dinosaur
Herbivore
It was a plant eating dinosaur.
wqdd
xousarusose
The "Brontosaurus" isn't even a real dinosaur at all. It was just a mistake. And it wasn't the largest flesh-eating dinosaur. "Brontosaurus" was an herbivore, so it ate only plants.
There were many large plant eating dinosaurs. The largest, however, were sauropods, which had long necks and ate leaves high in the forest canopy. One of the largest sauropods was the Argentinosaurus, which measured up to 115 ft long and 100 tons.
xiarousus
A Herbivore.