No, a Trex is bigger. Their prey included ornithopods, stegosaurids and sauropods, and there may have been some cannibalism.
Giganotosaurus spinosaurus carcharodontosaurus and allosaurus.
Since they were large, predators wouldn't dare hunt a baby allosaurus.
it is were it kinda lies
Allosaurus definitely would have hunted young Brachiosaurus. It would ambush, then pursue and grasp the prey with its arms, and dispatch it with a bite to the throat. It is unknown whether Allosaurus hunted adult sauropods, but if they did, Allosaurus would have to mob the sauropod as a group and slash it repeatedly until the prey finally bled to death.
I believe you are thinking of Ceratosaurus. Ceratosaurus wasn't large enough to hunt adult sauropods, but could hunt young ones or scavenge on adults. Allosaurus, however, was much larger, so Ceratosaurus would have to wait for its turn if it wanted to scavenge at the same site as Allosaurus.
Allosaurus was a 28 foot long, one to four ton carnivore, depending on the weight estimate you use. Adults would have hunted large, herbivorous dinosaurs, such as Camptosaurus, Dryosaurus, and Stegosaurus. In addition, Allosaurus may have gathered in groups on occasion to hunt massive sauropods such as Diplodocus, Brachiosaurus, Camarasaurus, or Apatosaurus.
Allosaurus was dominant over Ceratosaurus, but Ceratosaurus would not be usual prey for Allosaurus. Carnivore almost never prey on other carnivores. It is possible though on rare occasions Allosaurus may hunt and kill a Ceratosaurus for food.
Trex
Capitalize trex when you are using it as a proper noun, such as a specific thing or trademark.
Yes
trex
There is one accepted species in the Allosaurus genus. Its full Latin (or scientific) name is Allosaurus fragilis.